Mic

The skin infection of the foot of a farmer as illustrated in the upper photograph was caused in a farmer when walking barefoot in soil contaminated with a filariform larva. Based on the morphology of the 50 µm in diameter ovum (lower image), select from the question/answer list the species that is the presumptive cause of this infection.

Necator americanus

The identification of Neisseria species is most often confirmed by observing the specific carbohydrate utilization profile (glucose/dextrose; maltose; lactose; sucrose; yellow is a positive reaction). Based on the carbohydrate reactions as observed in the image, identify the organism:

Neisseria meningitidis

Gram-negative cocci that occur in pairs with their adjacent sides flattened, giving them a "coffee bean" appearance (indicated by the arrows in the image), are typical of which of the following bacteria?

Neisseria species

Dracunculus medinensis belongs to this category of parasites?

Nematode

Enterobius vermicularis (pinworm) is classified as which of the following?

Nematode

In which of the following categories does the helminth Ascaris lumbricoides belong?

Nematode

Trichuris trichiura belongs to which of the following helminth groups?

Nematodes

Which of the following choices represents the characteristic indicator, fermentable sugar(s), and bacteriostatic agent(s) that are present in MacConkey agar respectively?

Neutral red / lactose / bile salts and crystal violet

An urinalysis is commonly performed to detect bacteriuria or pyuria. In an urinalysis, tests are performed that serves as a method of screening for urinary tract infections. Which of following tests detect bacteria that produces enzymes to reduce nitrate?

Nitrate reduction test

If a positive result for a rapid HIV test is obtained, all of the following are possible next steps EXCEPT:

No additional testing required

Specimen handling from patients with symptoms consistent with tularemia requires work in a biological safety cabinet. Although PCR may confirm infection with Francisella tularensis, the following culture characteristics and tests aid in presumptive identification:

No growth on MAC, slow growth on CHOC; oxidase negative, positive catalase and ß-lactamase

Patterns of hydrolysis of tyrosine, xanthine, and casein are characteristics helpful in making species identifications within which genera?

Nocardia

A sputum sample from a patient with a pulmonary abscess is received in the laboratory. After several days of incubation the following findings are noted: Yellow, irregular colonies growing on a blood agar plate (BAP) under aerobic conditions. Acid-fast stain shows that the organisms are partially acid-fast. Which of the following organisms should be suspected?

Nocardia asteroides

Which of the following statements is true about the emergence of penicillin-resistant strains of Streptococcus pneumoniae?

A zone size of = 20 mm with the oxacillin disk screen must be confirmed with an MIC method to determine if Penicillin is susceptible or resistant.

Illustrated in the top image is 4 day growth of a smooth, glabrous colony with a light tan yellow surface, cultured from a patient who developed a subcutaneous abscess at the site where a bone marrow transplant was administered. The bottom image is a photograph of a methylene blue stained mount presenting long, delicate conidiophores at the tips of which are produced loose clusters of thin elongated conidia in an oriental letter or "diphtheroidal" pattern. With these observations, what is the most likely identification?

Acremonium sp.

A microbiologist performed a Gram stain procedure on a sputum specimen and was unable to determine if what was seen on the smear were tiny, Gram negative organisms or stain debris. Which of the following stains would help the microbiologist make a correct determination?

Acridine Orange

Which of the following stains binds to nucleic acid to aid in the detection of cell wall deficient organisms?

Acridine Orange

Which of the following stains binds the nucleic acids of the cells and requires a florescent microscope for reading?

Acridine orange stain

Illustrated in the upper image is a stained histological section of a bowel showing a heavy inflammatory reaction within which 10 - 12 µm spherical cysts are observed. The lower image is a close up view of one of the trophozoites from a smear preparation of the exudates. There is a distinctive central karyosome, even distribution of the ring of chromatin, and the finely granular cytoplasm. What disease can be presumptively reported?

Amebiasis

Many organisms have developed resistance to antibiotics. What mode of resistance has MRSA acquired?

Acquisition of new targets

This suspicious form measures 15 µm and was recovered in stool. Which of the following conditions is associated with the presence of this form?

Amebiasis

Illustrated in the top image is a 3.5-day-old brown/black, smooth yeast colony that is usually considered a contaminant when recovered in laboratory cultures. Reports of verrucose skin and visceral infections with this black yeast have been reported. The bottom image illustrates the microscopic view as prepared in a mount prepared from the surface of the colony. Note the background dark-staining hyphae from which are produced small, elliptical conidia. Select from the choices below the correct presumptive identification of this isolate.

Aureobasidium pullulans

All of the following are synonyms of the 2009 Influenza A H1N1 virus EXCEPT?

Avian flu

Which of the following morphologic structures on the Giardia intestinalis trophozoite is pictured in the section labeled B?

Axonemes

Most infections caused by Streptococcus anginosus can be treated with any of the following antibiotics, EXCEPT:

Aztreonam

All of the following are Lancefield carbohydrate antigens found on beta hemolytic Streptococcus species. All of the following antigens are found on organisms from the Streptococcus anginosus group EXCEPT?

B

The four mycobacteria shown have been cultured on Middlebook agar and include the duration of their incubation. Which of the organisms is most characteristic of the growth seen with Mycobacterium kansasii?

B

A 58-year-old male, who recently returned from an extensive overseas business trip to Africa, presented to the local clinic complaining of nausea, vomiting, and an achy feeling all over his body. At first, he thought it was just the flu, but it persisted. The doctor ordered a battery of tests including blood smears for parasitic study. This suspicious form was recovered. The patient is most likely suffering from:

Malaria

Although not always the most practical, animal inoculation may be used to identify all but which of the following conditions?

Malaria

A patient is seen at his physician's office for scaling, flat lesions on his back that are irregular with white blotches of discoloration (top image). The bottom image shown is of a tease mount taken from the skin and stained with Periodic Acid Schiff, which reveals narrow fungal hyphae (arrows) along with 3 - 5 µm in diameter, irregular sized spherical budding yeast cells, a presentation often referred to as "spaghetti and meatballs". Which fungi is the most likely cause of infection?

Malassezia furfur

A track star was in the locker room after a competition when one of his teammates noticed light brown circular lesions on his upper back. The agent MOST likely responsible for this condition is:

Malassezia furfur

All of the following statements are true regarding the significance of performing direct microscopic examinations of specimens for culture, EXCEPT:

Allows the microbiologist to discard the sample and cancel testing if no organisms are observed.

Large, gray to white, beta hemolytic colonies were isolated on sheep blood agar from a peritoneal fluid. The following biochemicals were performed: Gram Stain: Gram positive cocci in chains and pairs Catalase: Negative PYR: Positive Bacitracin Sensitive Identify the organism from the choices provided.

Alpha hemolytic streptococcus species

Illustrated in the left tube of this photograph is a positive Voges Proskauer reaction (left tube). The red pigment is produced from the reactions of:

Alpha naphthol with diacetyl

The microscopic illustration demonstrates the golden-brown pigmented conidia and macroconidia of the following mold:

Alternaria

Which of the following is the first stage in the life cycle of a hemoflagellate?

Amastigote

Binary fission is the means of reproduction for which of the following groups of parasites?

Amebae

With its ability to grow at 45° C, the Aspergillus species most commonly recovered from hospital heat vents and air ducts, serving as the primary environmental source of hospital-acquired respiratory infection, is:

Aspergillus fumigatus

Illustrated in the composite image on the left is a 72-hour growth on Sabouraud's dextrose agar of a finely granular, black pigmented colony obtained from a subcutaneous abscess at the site of an intravenous transfusion. The image to the right illustrates the microscopic appearance of a small inoculum taken from the surface of the center portion of the colony. A small spherical vesicle is surrounded by a row of phialides producing small, black-staining conidia. With these observations, select from the multiple choices the name of the fungus species as presented.

Aspergillus niger

The image on the right of a mold colony on an agar plate is most representative of which of the following molds?

Aspergillus niger

Which Aspergillus species show biseriate with phialides covering the entire surface of a spherical vesicle with black conidia as microscopic morphological features?

Aspergillus niger

The infectious diseases listed below are listed with the most commonly associated bacterium, EXCEPT:

Aspergillus niger - "Black lung"

All of the following fungi are appropriately listed with their respective morphology, EXCEPT:

Aspergillus sp. produce ascospores

A farmer is diagnosed with a fungal respiratory infection. A fungal culture demonstrates rapid growth of a blue-green colony on fungal media. Microscopically, the organism demonstrated septate hyphae with long conidiophore ending in a dome-shaped vesicle. Long chains of conidia protrude from the vesicle as demonstrated in the illustration. The most likely identification is:

Aspergillus species

Based on the structures observed in this microscopic image, the most probable identity of the fungus recovered from an induced sputum specimen is:

Aspergillus species

Choose the fungi that may be identified to a genus level, when the fungal structures that are seen in this photomicrograph are present in tissue sections.

Aspergillus species

What organism matches the tissue morphological features of separate hyphae, 5-10 µm in diameter that exhibit dichotomous branching?

Aspergillus species

Illustrated in the upper left image of the composite photograph is a 3 day old colony with a central, granular yellow surface (resembling cinnamon) surrounded by a broad white apron. This colony was recovered from a fungus ball infection of the lung. The microscopic presentation of a methylene-blue stained mount of a sample from the surface of the colony is observed in the upper right and lower left images. In the lower right image taken of a direct mount of the colony showing vegetative hyphae. With these observations, select from the list of multiple choice responses the correct fungal species as presented.

Aspergillus terreus

Which Aspergillus species, when cultured, will have colonies that resemble powdered cinnamon?

Aspergillus terreus

A 70-year-old man who three days previously had incurred a cerebral vascular accident was semi-comatose and having difficulty breathing. He developed sudden fever overnight and was found to have pneumonia. The Gram stain shown in this photomicrograph was obtained from purulent material obtained through the intubation tube.What is the most likely type of pneumonia?

Aspiration pneumonia

A clean-catch midstream urine specimen from a 30-year-old woman was sent to the microbiology laboratory for culture. The patient had no urinary symptoms, but the urine culture grew out 100,000 cfu/mL of Escherichia coli from two cultures collected 24 hours apart. Which of the following categories would the patient be classified?

Asymptomatic bacteriuria in female patients

Which of the following statements is TRUE with regard to the agents of bioterrorism?

At least a class II biological safety cabinet (BSC) should be used.

The pair of nonfermentative gram negative bacilli producing the motility reactions illustrated in the left (motile) and right (nonmotile) tubes respectively shown in the photograph are:

Bordetella bronchiseptica and Acinetobacter baumannii

An aerobic Gram negative coccobacillus was isolated from a nasopharyngeal swab 48 hours after culture from a 6-month-old with the following culture characteristics on Bordet-Gengou agar: Small zones of beta-hemolysis Urease: positive (24 hours) Oxidase: negative Motility: negative The MOST probable identification of this isolate is:

Bordetella parapertussis

A gram-negative coccobacillus produces small gray colonies surrounded by a zone of hemolysis on potato-blood-glycerol agar. The organism also grew on chocolate agar, but NOT on sheep blood agar. This is MOST likely to be which organism?

Bordetella pertussis

Bordet-Gengou plates are used to isolate:

Bordetella pertussis

Bordet-Gengou potato infusion agar is the medium of choice for the recovery of which one of the following organisms?

Bordetella pertussis

Which of the following organisms is best visualized by use of a darkfield microscope?

Borrelia

Which of the following growth factor(s) is necessary for the proper culture of Haemophilus influenzae?

Both X and V factors

Which of the following statements concerning vancomycin resistance in Enterococci is TRUE?

Both ampicillin and vancomycin resistance are found more frequently in E. faecium than in E. faecalis.

A cancer patient was admitted to the hospital with fever, tachycardia, and a drop in blood pressure. Due to the patient being treated for cancer, her chemotherapy had been administrated through an intravenous catheter. To rule out a catheter-related infection, the physician ordered two sets of blood cultures with one set being collected from the catheter site and the second set being collected by venipuncture. After 48 hours, the patient had positive blood cultures that grew Staphylococcus epidermidis. How will the physician know if the Staphylococcus epidermidis present is due to an infected catheter or is a contaminant?

Both blood culture sets (catheter and venipuncture) will be positive

A physician called the microbiology laboratory and asked what he needed to order to diagnose Bordetella pertussis from a child who had what appeared to be having whooping cough. Which of the following should the physician be told to order?

Both direct fluorescent antibody (DFA) test and culture

Illustrated in this photograph is a positive slide coagulase test (Image B) compared to a negative control (Image A). The clumping of the bacterial cells, as seen in Image B, results from the bacterial production of:

Bound coagulase

All of the following are commercial methodologies that Chlamydia and Neisseria identification have been based on?

Branched chain DNA technology

A gram positive bacillus that has a rod-coccus cycle (short, thin rods in young cultures and cocci in older cultures) and an odor resembling cheese is:

Brevibacterium spp.

The best clinical specimen for the recovery of Legionella pneumophilia is:

Bronchial washings

The recovery of Mycoplasma hominis from the genital tract of females has been associated with all of the following clinical syndromes EXCEPT:

Bronchitis

Which of the following specimen types should be centrifuged prior to performing the Gram stain and culture?

Cerebrospinal fluid (CSF)

What is the optimal specimen type to diagnose a Naegleria fowleri infection?

Cerebrospinal fluid(CSF) sample

A 68-year-old female, who recently vacationed in Brazil, presented to her physician exhibiting overall weakness, fever, and enlarged lymph nodes. Blood was collected for culture and parasitic examination. The culture was negative. This suspicious form was recovered upon examining the Giemsa-stained preparation. This patient is most likely suffering from what condition/disease?

Chagas disease

In the photomicrograph, circulating trypomastigotes are observed on a blood smear. The trypomastigotes are identified as Trypanosoma cruzi. The infection rate has increased and was linked to a transfusion-transmitted disease. What disease does this parasite cause?

Chagas disease

Which of the following conditions is caused by Trypanosoma cruzi?

Chagas' Disease

Trypanosoma cruzi is the etiologic agent of:

Chagas' disease

The media used to isolate Legionella pneumophilia should contain which of the following additives?

Charcoal and yeast extract

This artifact, when seen, is indicative of intestinal inflammation and is characteristic of a number of parasitic infections is known as (a):

Charcot-Leyden crystal

Daily activities by microbiology personnel should be performed to ensure patients receive the best care. All of the following activities should be performed daily EXCEPT?

Check to ensure autoverification of results is working correctly

Which age group has been most affected by the H1N1 virus?

Children

Which organism is considered nonpathogenic?

Chilomastix mesnii

The image to the right presents protozoan organisms in the cyst stage of development. Identify the protozoan cyst in Image D.

Chilomastix mesnili cyst

What organism (represented in the photomicrograph--showing a pear-shaped organism with a spiral groove across the ventral surface) is recovered from a stool sample and measures 15 µm by 8 µm?

Chilomastix mesnili trophozoite

Illustrated in the top photograph are smooth white yeast colonies growing on Sabouraud's heart infusion agar (SABHI agar) after 48 hours incubation at 30o C. The colonies were recovered from a post-operative wound infection in a 65-year-old man following an organ transplant. The bottom photograph is representative of more mature colonies after an additional 24-hour incubation. The isolate was also inoculated to Cornmeal Tween 80 Agar. What characteristics do you expect to see when examining the growth from this media?

Chlamydoconidia present on the hyphae

The following morphologic structure identifies Candida albicans and distinguishes it from most of the other Candida species.

Chlamydospore

Which of the following media contains the X and V factors necessary for the growth of Haemophilus influenzae?

Chocolate agar

A patient presents at the ER with severe diarrhea and dehydration, marked with rice water stool. The patient has travel history to India. A stool culture was obtained and grew comma-shaped, gram negative bacilli. What is the most likely diagnosis for this patient?

Cholera

Rice water stools that are most commonly due to ingestion of contaminated water and have been a major public health concern for centuries, exhibit colonies on TCBS agar consistent with those in the image to the right. These colonies are caused by a condition called:

Cholera

The following is an inclusion that may be round in the immature cyst of amoebae such as Entamoeba histolytica and Entamoeba coli. This inclusion is rod-shaped, contains refractile chromatin, and may have smooth, rounded edges or splintered ends. This structure is called:

Chromatoid bars

This isolate, identified as an Enterobacter cloacae, was recovered from the urine and blood cultures of a patient who had recently returned from India where he had received a total hip replacement. He presented to the ED with multiple decubiti, sinusitis and a urinary tract infection. The Hodge Test that was performed on this organism was negative. What resistance mechanism may be identified from the KB plate and the susceptibility interpretations?

Chromosomal AmpC plus Porin Mutation

Illustrated in the image to the right is a tube of tryptophane agar with a positive indole reaction, as seen by the red ring at the top of the medium. It is necessary to use xylene extraction and Ehrlich's reagent rather than the conventional Kovac's reagent when detecting indole production by which of the following organisms:

Chryseobacterium (Flavobacterium) meningosepticum

Based on the reactions observed in the tubes shown in the photograph (including open and closed OF dextrose and a positive nitrate reaction only after addition of zinc dust, as shown in the right tube of the pair labeled "Nit"), the most likely identification is:

Chryseobacterium spp.

Which of the following can produce indole?

Chryseobacterium spp.

The images to the right show a 4-day-old colony grown on Sabouraud's Dextrose agar (left image). It was recovered from what was considered a "contaminant" from a bacterial culture. The image on the right is a high power photomicrograph of a methylene-blue stained mount prepared from the surfaces of the colony. With these observations, select the fungus genus from the choices below.

Chrysosporium

Which of the following is the correct classification for Image C?

Ciliate

A Gram stain of drainage from an open wound revealed gram-positive bacilli with spores. This description would commonly rule out which one of the following organisms? (Choose the BEST response.)

Clostridium perfringens

A sample from a wound infection, suspected case of gas gangrene, was cultured and showed anaerobic colonies that are small, smooth, light gray-yellow and surrounded by a distinctive double zone of beta hemolysis (arrows). Gram stain, as illustrated in the lower photomicrograph, are large, non-spore forming, "box-car" shaped gram positive bacilli. What is this organism that is also related to outbreaks of food-borne diarrhea following ingestion of contaminated meat products?

Clostridium perfringens

The anaerobe growing on the surface of the blood agar plate, the toxins of which cause a form of necrotizing enteritis known as Darmbrand ("fire bowels") in Germany or "Pig bel" in New Guinea, is:

Clostridium perfringens

The following organism is an anaerobic organism that produces spores and a double-zone of beta-hemolysis.

Clostridium perfringens

Which of the following organisms is responsible for myonecrosis with gas gangrene, food poisoning as well as necrotizing enteritis, a life threatening that causes ischemic necrosis of the jejunum?

Clostridium perfringens

Which of the following organisms produces a double zone of hemolysis on blood agar?

Clostridium perfringens

The Gram stain shown in the image was prepared from a positive anaerobic blood culture bottle after 36 hours incubation. Based on the morphology of the bacterial cells (some with spores, noted by the blue arrows), what is the most likely identification?

Clostridium septicum

The flat, spreading gray-white colonies with an outer zone of beta hemolysis as observed on the surface of an anaerobic blood agar plate shown in the upper image were recovered from a blood culture of an elderly man leading to a potential diagnosis of cancer of the colon. Observed in the gram stain are short gram-positive bacilli, some with distinctive central and sub-terminal spores. From these observations, select the most likely isolate.

Clostridium septicum

The following is a spore-forming anaerobe that is associated with neutropenic enterocolitis:

Clostridium septicum

A 25-year-old man was experiencing some difficulty in chewing and swallowing food. He had incurred a deep laceration of the lower leg in a lawn mower incident one week before. The wound was healing but signs of infection persisted. The image shows the Gram stain of a spreading, gray colony isolated from an aspirate of the wound, incubated under anaerobic conditions. Three additional bacterial species were recovered on blood agar incubated aerobically. What is the most likely identification of this anaerobic organism?

Clostridium tetani

Cocci may arrange as diplococci, tetrads, chains and clusters. The morphologic arrangement of the genus Staphylococcus is:

Clusters

A patient with hydrocephalus had a shunt placed 3 weeks ago and is now experiencing symptoms consistent with a CSF shunt infection. When a CSF sample is sent to the microbiology department, the image on the right is observed on the Gram stain. What is the most likely cause of this CSF shunt infection?

E. coli

Which of the following serological tests would be used for the diagnosis of Q-fever?

EIA or indirect immunoflourescence

The Carba NP confirmatory test is used to detect all of the following carbapenemases EXCEPT?

ESBL (Extended Spectrum Beta-Lactamase)

Enterobacter cloacae colonies were isolated from a blood culture taken from a 45-year-old woman undergoing chemotherapy for breast cancer. Observe this Kirby-Bauer susceptibility plate and the result report form for this organism. From the multiple choices, identify the resistance mechanism (if any) that this organism demonstrates.

ESBL- Extended-Spectrum Beta Lactamase with Amp C expression

Humans serve as accidental hosts in the life cycles of which of these this parasites?

Echinococcus granulosus

What cestode, pictured here, resides in multiple tissues of the human body?

Echinococcus granulosus

All of the following represents an organism with an appropriate form of diagnostic procedure, EXCEPT:

Echinococcus granulosus - routine ova and parasite examination

The term "hydatid sand" is used in reference to which of the following tapeworms?

Echinococcus species

Following a diagnosis of tuberculosis, this physician moved to the Adirondack Mountains where he experienced an improvement in his health. He then opened a medical practice in Saranac Lake and founded the Adirondack Cottage Sanatorium where the standard of care for tuberculosis involved prolonged bed rest. Who is this physician?

Edward L. Trudeau

Illustrated in this photograph is a close-in view of colonies growing on the surface of xylose lysine deoxycholate (XLD) agar. The bacterial species most likely producing the colonies shown here is:

Edwardsiella tarda

The diagnostic stage for helminths is:

Egg

Clenched-fist cellulitis is commonly found in patients whom have been in a physical altercation. Which organism below is the most likely cause of this condition?

Eikenella corrodens

Illustrated in this photograph are colonies growing on the surface of a chocolate agar plate. The colonies were recovered from a subcutaneous infection of the forearm and had a bleach odor. The most likely identification is:

Eikenella corrodens

Loeffler's medium is useful in making the presumptive identification of isolates suspicious for Corynebacterium diphtheriae recovered from oropharyngeal cultures because it:

Enhances granule formation as seen in methylene blue stains

The following media contains specific nutrients that encourage the growth of a pathogen over the growth of other bacteria from a specimen. It is useful in the isolation of stool pathogens such as Salmonella and Shigella, the isolation of anaerobes, and the selective isolation of group B streptococci.

Enrichment media

A stool was received in the laboratory for parasitic examination on a 49-year-old female who just returned from missionary work in numerous developing countries around the world. The patient had been suffering from mild diarrhea over the previous two weeks. This suspicious form was seen. Notice in the image, five nuclei are visible. Upon focusing between two focal planes, a total of eight nuclei were observed. It measures 25 µm. What is the identification of this form?

Entamoeba coli

The 20 µm in diameter cyst illustrated in the photograph had been observed microscopically in a trichrome stained mount prepared from a stool specimen of a patient with low grade, intermittent diarrhea. What is the presumptive identification?

Entamoeba coli

Which of the following amoeba cyst measures around 25 µm?

Entamoeba coli

Which of the following amoeba is known to have 8 nuclei in the mature cyst form?

Entamoeba coli

The image to the right displays a protozoa measuring 25 µm that was found in stool. Which of the following does this image represent?

Entamoeba coli trophozoite

Not all strains of Entamoeba histolytica appear to be pathogenic, and recent molecular studies indicated that there was a non-pathogenic variant of Entamoeba histolytica. What is this non-pathogenic variant?

Entamoeba dispar

This photograph shows a positive reaction in each of the tubes with the tube on the left containing esculin medium and the tube on the right containing heart infusion broth with 6.5% sodium chloride. The bacterial species that characteristically produces these reactions is:

Enterococcus faecalis

Which of the following is the most commonly encountered enterococcal species?

Enterococcus faecalis

Which one of these Gram-positive species has a high incidence of vancomycin-resistance?

Enterococcus faecium

An alpha-hemolytic streptococcus isolated from a urine culture is resistant to optochin and bactracin, grows in 6.5% NaCI broth, and is PYR positive. The organism is MOST likely:

Enterococcus species

An alpha-hemolytic, catalase negative, Gram-positive coccus from a wound culture gave these additional results: Bacitracin resistantBile esculin hydrolysis positiveCAMP negativeNa hippurate hydrolysis negativePYR positive Which of the following would be the MOST probable identification?

Enterococcus species

This non-hemolytic organism was isolated from the blood culture of a patient. The image shows the organism's reactions in 6.5% NaCl broth and on bile esculin agar. With further testing, this isolate will most likely be identified as:

Enterococcus spp.

The images represent a gram-positive, catalase-negative, non-motile coccus inoculated to bile esculin agar as seen in the top image. The organism grows in 6.5% NaCl broth and the reaction on 6 µg/mL of vancomycin in Mueller Hinton agar is shown in the bottom image. The organism should be reported as:

Enterococcus spp., Resistant to vancomycin

Illustrated in the photograph to the right is the growth of bacterial colonies on blood and MacConkey agars. The media on the left with the red pigmentation on MacConkey agar indicates lactose fermentation. Note the sorbitol MacConkey agar plate on the right, which are growing non-pigmented, gray-white colonies. The isolate presented in this exercise is representative of the bacterial species that have been recovered from stool specimens in several outbreaks of patients with diarrhea following ingestion of contaminated ground beef. Which of the following is the identification of this isolate?

Enterohemorhragic E.coli (EHEC)

A dermatophyte that produces thin-walled, two or three-celled macroconidia in clusters, and no microconidia, most likely belongs to the genus:

Epidermophyton

A fungus culture from a toe-nail scraping demonstrates large, club-shaped macroconidia with no microconidia. The most likely identification is:

Epidermophyton floccosum

A stool culture is received and inoculated to sorbitol MacConkey agar, where is exhibits reddish-pink colonies. Based on this colony morphology, which one of the organisms below can you rule out?

Escherichia coli O157:H7

All of the following statements concerning biochemical reactions are true, EXCEPT:

Escherichia coli is positive for utilization of sodium citrate, as depicted in tube A.

Which of the following specimen processing techniques is based on the principle that parasites are heavier than sample debris and will be present in the sediment after being processed?

Ethyl acetate concentration

Illustrated in the top image is a 7-day-old colony with a gray-yellow, velvety mold and a black-staining perimeter extending to the reverse of the colony. Although characteristic of a colony of chomomycosis, what is the identification of fungi that produces the sharply pointed end of the phialide from which clusters of elliptical conidia are formed?

Exophiala jeanselmei

Illustrated in the upper image is an 8-day-old old green black colony growing on the surface of Sabouraud Dextrose Brain Heart Infusion (SABHI) agar, obtained from a superficial skin lesion characteristic of chromomycosis. The black pigment extends to the reverse side of the colony. The identification can be made by observing the characteristic fruiting body as illustrated in the lower image. What is the most likely identification of this fungi?

Exophiala jeanselmei

Which of the following dematiaceous fungal species produce conidia in clusters?

Exophiala species

Illustrated in this image is the fruiting head of one of the fungal agents of chromomycosis. Note the small clusters and short chains of elliptical conidia produced from the tip of a conidiophore. Which of the following choices best represents the type of sporulation illustrated in this image?

Exophiala sporulation

From the four specimens listed for Gram stain and culture, which one should be rejected?

Expectorated sputum in sterile container for anaerobic culture

Illustrated in the top photograph is a circumscribed colony after 3 days of incubation at 30o C. The consistency is cottony to wooly and pigment ranges from gray to deep brown. A light pigmented outer apron is seen at the margins of growth. The reverse is dark brown to black, resulting from a darkly pigmented mycelium. As the colony morphology is not species specific, the identification can be made by the appearance of the macroconidia observed in a stained tease mount made from the surface of the colony as observed in the bottom photomicrograph. From these observations, select from the multiple choices the name of this fungus.

Exserohilum species

The long, pencil-shaped, multi-celled, thin, and smooth-walled macroconidia illustrated in this image are characteristic of which species?

Exserohilum species

A 40-year-old male recently completed a two-week hiking expedition in Russia. Upon his return to the United States, the man presented to his physician complaining of severe foul-smelling diarrhea and abdominal discomfort. The doctor immediately suspected a parasitic infection and ordered stool for examination. The sample was loaded with this suspicious form that averaged 13 µm in length. This patient is most likely suffering from:

Giardiasis

Which stain is used specifically to detect Histoplasma capsulatum in blood and bone marrow?

Giemsa

The hyaline mold illustrated in this photomicrograph can be identified as:

Gliocladium species

Which of the following sugars has been fermented when a gram-negative bacillus produces an alkaline slant and an acid butt on triple sugar iron agar (TSI)?

Glucose

The set of tubes in the image to the right are the Hugh and Leifson Oxidative/Fermentative (O/F) basal medium with glucose and a pH indicator of bromthymol blue. This image demonstrates a reaction of:

Glucose non-oxidizer

In rapid carbohydrate fermentation testing, Neisseria gonorrhoeae ferments the following sugar(s):

Glucose only

The reactions in the tubes illustrated in this exercise (reading from left to right: TSI, Pseudosel, OF glucose closed, and OF glucose open) indicate that the bacterial species in question is:

Glucose oxidizer

An autopsy of a 1-year-old female admitted to the emergency room 4 hours prior to her death revealed Waterhouse-Friderichsen syndrome. Blood and nasopharyngeal cultures taken prior to her death should reveal an oxidase-positive, Gram-negative diplococcus with the following biochemical reactions:

Glucose positive, Maltose positive, Lactose negative and Sucrose negative

Examine the amoeba cyst illustration on the right. The internal structure at letter D is:

Glycogen mass

The presence of Gram negative intracellular diplococci in a genital specimen from a male is diagnostic of which disease?

Gonorrhea

Which of the following is most commonly used as a routine staining technique in the clinical microbiology laboratory?

Gram

All of the following would be suitable for identification of bacterial antigens, EXCEPT?

Gram Stain Reactions

The staining reaction for yeast is:

Gram positive

A thick peptidoglycan cell wall is MOST often associated with which of the following?

Gram positive bacteria

How would you classify the organism on this gram stain?

Gram positive cocci

The included Gram stain was made from a CSF specimen submitted to the laboratory. Select the appropriate reporting for the organisms seen.

Gram positive cocci in chains

Gram positive cocci in clusters and tetrads were seen on a clinical Gram stain taken from an open wound. Which of the following would be the MOST appropriate preliminary report?

Gram positive cocci in clusters and tetrads

Which of the following statements reflect accurate identifications of Enterococcus species?

Gram positive cocci in pairs or chains, catalase negative, esculin positive, PYR positive, vancomycin intermediate, motile, yellow pigment: Enterococcus casseliflavus.

Based on the image to the right, the issued gram stain report should read, "Many WBC with..."

Gram positive cocci in pairs.

Observation of each of the following characteristics is helpful in differentiating between Nocardia species and Mycobacterium species EXCEPT:

Gram positive staining

Two sputum specimens were submitted to the Microbiology laboratory for culture. A Gram stained smear was evaluated for each specimen prior to culturing. The fields that are shown in these images are representative of the 20 - 30 low power fields (lpf) that were examined. Which one of the two results represents a sputum specimen that is acceptable for culturing?

Gram stain A

Which substance acts as a mordant in the Gram stain process?

Gram's iodine

A group of Canadian travelers were visiting the island of Kauai in Hawaii for a summer vacation. They noticed a cave in the middle of the island that contained a 10 ft deep pool of water. Much to their surprise, they were the only individuals enjoying this newly discovered swimming hole. A few days later, all swimmers became ill. Their physician believed they all had Weil disease. Which of the following organisms can cause this disease?

Leptospira interrogans

Which spirochete is a causative agent of human disease and is acquired through contact with the urine of carrier animals?

Leptospira interrogans sensu stricto

Blood specimens are typically sterile; however, if an organism is suspected, a peptide nucleic acid probe (PNA) FISH can be used to identify the organism directly from the specimen. Which of the following microscopes can be used to exam PNA FISH slides?

Fluorescent microscope

A group of relatively slow growing fungi with distinctive dark brown to black colonies are the cause of infections of the skin known as Chromoblastomycosis. Clinically they appear as roughened multicolored verrucous vegetations, most commonly spreading over the dorsal surfaces of the lower legs and feet following penetrating injuries. A presumptive diagnosis of a fungus infection can be made on H & E - stained sections of a tissue biopsy by identifying oval/spherical bodies grouped in small clusters termed "sclerotic bodies" (more colloquial known as "copper pennies"), as illustrated in the top image. Dark gray-black pigmented mold colonies are grown in culture obtained from a biopsy specimen. The dark pigment is produced by deeply pigmented hyphae from the production of melanin, as illustrated in the bottom image. Note the branching conidiophores borne from the tips of hyphae giving rise to short chains of oval conidia. Select the presumptive species identification of this isolate.

Fonsecaea pedrosoi

Illustrated in the top image is a slow-growing, 8-day-old colony with velvety brown, deep radial grooves and a black periphery consistent with one of the agents of chromomycosis. In the bottom image, note the conidiophores produced from the sides of the hyphae producing short, branching phialides, giving rise to clusters of elliptical conidia. From the list of choices shown below, select the correct presumptive identification of this isolate.

Fonsecaea pedrosoi

Which of the following conditions is associated with a typical Bacillus cereus infection?

Food borne enteritis

A 40-year-old male just returned from a six-month tour of the Far East. He went to his doctor upon his return complaining of weakness, diarrhea, fever and cough. Upon questioning the patient it was learned that he spent many an evening swimming in the various local fresh water ponds. The doctor, suspicious of a parasitic infection, ordered a stool for examination. Two suspicious forms were seen: form 1 is roundish and measures 77 µm by 62 µm. Form 2 is long and ladder-like and lays on the edge of form 1. What are these two structures?

Form 1 - cyst; Form 2 - artifact

Which bacterial genus contains fastidious, facultative intracellular, gram-negative bacilli that causes a zoonosis called tularemia?

Francisella

The well circumscribed cutaneous papule with the distinct outer erythematous border illustrated in the upper photograph developed over a period of 5 days at the site of a tick bite. The lower photograph illustrates colonies growing on a buffered charcoal yeast extract agar plate that had been inoculated with material from the ulcer bed three days before. Tiny, pale-staining Gram negative coccobacilli were seen on Gram stain. The most likely causative agent is:

Francisella tularensis

Agar plates on a positive blood culture are incubated for 48 hours and no growth is visible on the agar plates. The tech reviews the initial Gram stain from the blood culture bottle, which reveals tiny pleomorphic Gram-negative coccobacilli. What organism should the tech suspect and what should the tech do next?

Francisella tularensis; Sub blood culture bottle to a media with cysteine for optimal growth

A microbiologist was surprised when he could not recover Helicobacter pylori from gastric biopsies in which organisms were seen in the tissue sections. He was advised to switch from the Campy BAP selective medium to Skirrow's blood agar because the latter is:

Free of cephalothin

When a fungus is suspected in causing a cutaneous infection, there are several methods that can be used to identify the fungus. To help identify a fungal isolate from tissue specimens, which of the following methods will be most beneficial?

Fungal Culture

The image to the right is a depiction of a typical field observed on a KOH prep. What is the element observed in this image?

Fungal hyphae

In tissues infected with Histoplasma capsulatum, which of the following is usually true?

Fungus is usually intracellular

Based on the results of in-vitro susceptibility testing, patients with septicemia from each of the bacterial species listed below can potentially be treated with vancomycin EXCEPT:

Leuconostoc species

In an urinalysis, tests are performed that serve as a method of screening for urinary tract infections. Which of following tests detects the presence of inflammatory cells?

Leukocyte esterase test

Which of the following cells will have detectable virus in the peripheral blood during active CMV infection?

Leukocytes

The minimum time of retention for microbiology instrument records is?

Life of the instrument

The biochemical testing results of an alpha-hemolytic streptococcus show that the isolate is bile esculin-positive, but does not grow in the presence of 6.5% NaCl. The MOST PROBABLE identity of this isolate is:

Group D streptococcus, non-enterococcus

A 30-year-old man with chronic persistent hepatitis developed an abscess in the right hepatic lobe. A needle aspiration revealed purulent material. The small colonies shown in the upper photograph were isolated after 36 hours incubation at 35°C. They emitted a butter scotch odor. The lower photomicrograph reveals the gram stain features. The antigen most likely carried by this isolate is:

Group F

All of the following descriptions about Pasteurella species are true, EXCEPT:

Grows well on MacConkey agar.

A key laboratory characteristic by which Mycobacterium bovis can be separated from Mycobacterium tuberculosis is:

Growth inhibition by thiopine-2-carboxylic acid hydrazide (T2H)

What is a major reason why there is no viable HIV vaccine available on the market?

HIV has a high mutation rate due to the lack of proofreading ability by reverse transcriptase

Current CDC (2014) recommendations for initial HIV screening include FDA-approved immunoassay for detection of:

HIV-1 and HIV-2 antibody, HIV-1 p24 antigen

Which of the following is also known as the Koch-Weeks bacillus?

Haemophilus aegyptius

Which strictly human pathogen causes chancroid, a highly contagious, sexually transmitted genital ulcer disease?

Haemophilus ducreyi

A 21-year-old female developed painful swelling of the left knee along with a low grade fever. The knee was painful to palpation, an effusion was evident, and the overlying skin was slightly erythematous. Fluid was aspirated and a gram stain was performed (as seen in the images to the right). Based on the Gram stain morphology, which of the following bacterial species is LEAST likely to serve as the etiologic agent in the case described?

Haemophilus influenzae

A 42-year-old chain smoker experienced an increase in cough, sputum production, and intermittent shortness of breath for over one week. A diagnosis of chronic bronchitis with acute exacerbation was made. The image shows a Gram stain of an early morning, spontaneously expectorated sputum. Based on the pleomorphic coccobacilli shown in the Gram stain, what is the most likely cause of the exacerbation?

Haemophilus influenzae

A joint fluid was received in the microbiology laboratory. The specimen was cloudy with many neutrophils and Gram negative coccobacilli seen on the Gram stain. The specimen was inoculated to sheep blood and chocolate agar and grew a small, gray to tan colony on chocolate with no growth observed on the sheep blood. Which of the following is most likely the organism?

Haemophilus influenzae

A pediatric patient arrived at the doctor complaining of itching eyes that appeared red and slightly purulent. When a sample was submitted to the laboratory, the sample grew only on the chocolate plate as seen in the upper image. When performing a satellite test, the image on the bottom is observed. What is the most likely identity of the organism causing this patient's symptoms?

Haemophilus influenzae

Acute obstructive epiglottitis, both in adults and children, is most commonly caused by a specific bacterial species that can be recovered on chocolate agar and requires both hematin and NAD. The most likely identification is:

Haemophilus influenzae

An eleven-year-old girl was seen in the emergency room with sudden onset of sore throat, fever and dysphagia, the latter accompanied by an intermittent sensation of choking. The bacterial species shown in the upper photograph of a chocolate agar plate was recovered from a throat culture. The most likely bacterial species based on the test shown in the lower photograph is:

Haemophilus influenzae

Illustrated in this photograph is the surface of a 5% sheep blood agar plate on which are growing colonies of yellow pigmented Staphylococcus species. Note the tiny semi-translucent colonies that satellite around some of the colonies. Pleomorphic gram-negative bacilli were seen on gram stain. The most likely identification is:

Haemophilus influenzae

In the image to the right, small, minute, colonies are growing around a colony of Staphylococcus aureus on sheep blood agar. Which of the following organisms is this a characteristic?

Haemophilus influenzae

Satellitism observed in cultures is most commonly associated with which of the following bacteria?

Haemophilus influenzae

Sheep's blood agar is least suitable for the growth of which of the following organisms?

Haemophilus influenzae

The colonies growing on blood agar (upper image) were recovered from a sinus aspirate from a patient with acute sinusitis. The large, Staphylococcus colonies are obvious; however, note the satellite growth of small colonies. Small, Gram negative coccobacilli are observed in Gram stains. The pattern of bacterial growth around the X and V filter paper strips in the image to the right confirms these satellite colonies are Factor X and V dependent. From the list of multiple choices, select the name of this isolate.

Haemophilus influenzae

The term "HACEK" is often associated with infective endocarditis. All of the following organisms are included in the "HACEK" group, EXCEPT?

Haemophilus influenzae

This organism has been placed in trypticase soy broth and then streaked on a nutrient agar plate. Strips containing X, V, and XV were place on the plate and it was incubated 24 hours in CO2 conditions. With this information and the picture to the right, what is the identification of this organism?

Haemophilus influenzae

Which of the following organisms would show as negative for the testing shown in the image?

Haemophilus influenzae

The appearance of small colonies, growing adjacent to large Staphylococcus aureus colonies on the surface of the sheep blood agar plate indicates the need for Factor V for growth (upper photograph). This is confirmed by the VX filter paper test in which growth is observed only around the V impregnated strip, but not around the X filter paper disc. Factor X is included in the agar medium. With these observations, select from the multiple choices the name of this isolate.

Haemophilus parainfluenzae

5% sheep blood agar will support the growth of most strains of the following organisms, EXCEPT:

Haemophilus spp.

An uncommon isolate in clinical laboratories, the gray-white colony with a hairy mycelium as illustrated in the top image is non-specific. The identification is made by microscopically observing acid-fast ascospores as seen in the bottom image. Select the fungal species characteristic of this isolate.

Hansenula anomala

A new tech has a presumptive Salmonella species via biochemical identification on a stool culture. To confirm, serological testing is performed. The serological testing is negative and the quality control which was run simultaneously passed. What should the tech do next?

Heat a suspension of the organism and then repeat the serological testing

A new tech has a presumptive Shigella species via biochemical identification on a stool culture. To confirm, serological testing is performed. The serological testing is negative and the quality control which was run simultaneously passed. What should the tech do next?

Heat a suspension of the organism and then repeat the serological testing

When serotyping Salmonella typhi, false negative reactions can occur when testing. For example, a Salmonella typhi isolate tested Vi antiserum positive and O antiserum negative. What should be done next?

Heat specimen and repeat O antiserum test

A microbiologist was performing Shigella serotyping on a probable Shigella isolate and the organism did not serotype. The microbiologist was adamant that the organism was a Shigella species because it was lactose negative on Hekton-Enteric agar and non-motile in motility agar. What should the microbiologist do to ensure that false negative testing did not occur?

Heat specimen for 15 minutes and repeat testing

From the multiple choices below, select the most appropriate culture medium for optimum recovery and differentiation of Salmonella and/or Shigella.

Hektoen enteric (HE) agar

The colonies growing on the surface of a thiosulfate citrate bile sucrose (TCBS) agar plate (the green color indicates lack of sucrose fermentation) were identified as Vibrio vulnificus. The serious complication of infections with this bacterial species is:

Life-threatening septicemia

Which one of the following combinations of organisms would be appropriate positive and negative controls to verify the specific test functions listed?

Indole - Escherichia coli and Klebsiella pneumonia

Each of the following laboratory characteristics can be used to separate Bacteroides fragilis from the closely related Prevotella/Porphyromonas group of anaerobes EXCEPT:

Indole production

Elizabethkingia is the new genus name for the bacterium formerly called Chryseobacterium meningosepticum, an important agent of neonatal mentingitis (now E. meningoseptica). What biochemical characteristic is unique for the family Flavobacteriaceae among the nonfermenters?

Indole production

If a bacteria produces the enzyme tryptophanase to break down the amino acid tryptophan, which of the following tests will be positive with Kovac's reagent?

Indole test

Which combination of test/quality control organisms is correct? (One organism positive for the test and one organism negative for the test)

Indole: Escherichia coli and Proteus mirabilis

The bacterial species shown on the blood agar plate illustrated in the photograph was recovered from a blood culture of a patient with fever. The most likely source of infection is which of the following?

Indwelling catheter

Corynebacterium jeikeium is often associated with which of the following conditions?

Infected indwelling devices in AIDS patients

What term is defined as the presence of arthropods in or upon a human host:

Infestation

Which of the following types of influenza tends to be more severe than the others?

Influenza A

The glycoproteins neuraminidase (NA) and hemagglutinin (HA) are used to subtype the following virus:

Influenza A Virus

The liver fluke, Fasciola hepatica can be identified by its relatively small size the cone-shaped anterior extension (arrow). How do humans become infected with this organism?

Ingestion of poorly cooked water plants

Enterobius vermicularis infection is acquired by:

Ingestion or inhalation of egg

Which of the following anthrax infections is also known as "woolsorter's disease"?

Inhalation anthrax

Penicillin G, ampicillin, carbenicillin, and methicillin are antimicrobial agents whose MAIN biological function is to:

Inhibit cell wall synthesis

The area of suppressed growth surrounding a disk impregnated with an antimicrobial on a sensitivity plate is referred to as the zone of:

Inhibition

The susceptibility of a bacterium to each drug on a sensitivity plate using antibiotic disks is demonstrated by the diameter of the zone of:

Inhibition

Streptococcus pneumoniae can be isolated from peritoneal fluid and identified by molecular testing. One method of testing used to identify Streptococcus pneumoniae is molecular hybridization. All of the following steps must be followed to ensure that false positive results do not occur when testing for Streptococcus pneumoniae EXCEPT?

Inhibitors must be removed

Which fungal culture media is used for the primary recovery of pathogenic fungi exclusive of dermatophytes?

Inhibitory mold agar

Which of these describes the mode of action of the beta-lactam class of antibiotics?

Inhibits cell wall synthesis

A swab specimen from a wound culture is received in the laboratory. How should this specimen be processed for culture and Gram stain?

Inoculate organism plates for culture, then roll the swab back and forth on the slide

When determining the identification of an amebic parasite, which morphologic structures are most helpful in distinguishing them from one another?

Internal and external structures

A 20-year-old female was admitted into the hospital complaining of 10 to 15 bloody mucous stools per day, fever, gastrointestinal disturbances, abdominal pain, and nausea. The preliminary O & P report went out as "Probable Entamoeba histolytica trophozoites and cysts, confirmation pending." This patient is most likely suffering from:

Intestinal amebiasis

A 20-year-old female was admitted into the hospital complaining of 10 to 15 bloody mucous stools per day, fever, gastrointestinal disturbances, abdominal pain, and nausea. The preliminary O & P report went out as "Probable Entamoeba histolytica trophozoites and cysts, confirmation pending." What is this patient most likely suffering from?

Intestinal amebiasis

How should the organisms that are indicated by the arrows be reported?

Intracellular gram-negative diplococci

This suspicious form measures 18 µm and was seen in ova and parasite exam from a stool specimen. The most likely identification is:

Iodamoeba b?tschlii

The illustration demonstrates a non-pathogenic amoeba described as being 5-20 µm, containing a large glycogen mass, and a single nucleus with a large karyosome and no peripheral chromatin:

Iodamoeba b?tschlii cyst

A 27-year-old female graduate student recently returned from South America, where she completed a nature study of the rainforest. She spent months "living off the land." The woman went to her physician seeking treatment for a sinus infection, which she thought was responsible for several recent bouts of diarrhea. Upon questioning the patient, the doctor decided to collect stool for culture and parasitic examination. The stool culture was reported as "no enteric pathogens isolated." This suspicious form was seen on both wet preparations and on a permanent stain. It measures 17 µm. The identity of this form is most likely:

Iodamoeba butschlii

A 27-year-old male submitted a stool for culture and parasite study. The culture revealed no enteric pathogens. The suspicious form in the photograph was seen on the permanent trichrome stain. It measured 10 µm. Which of the following is the most likely identification?

Iodamoeba butschlii

Illustrated in the photomicrograph is an amebic cyst as observed in a stool specimen obtained from a patient with low-grade, intermittent diarrhea. Observe the distinctive cytoplasmic vacuole and "ball in socket" nucleus. Select from the list of responses the species identification of this amoeba.

Iodamoeba butschlii

The trophozoites indicated by arrows and the 10 µm oval cyst at the middle left in the photomicrograph were observed in a stool specimen from a person with mild intermittent diarrhea. What is the presumptive identification of this organism?

Iodamoeba butschlii

Each parasite listed below is correctly matched with its respective vector, EXCEPT:

Iodamoeba butschlii - pig

The organism illustrated on the right measures 12 µm and is found in stool. Can you identify it?

Iodamoeba butschlii cyst

This suspicious form shown in the trichrome stained image to the right measured 13 µm and was recovered from a stool sample There was no peripheral chromatin.

Iodamoeba butschlii trophozoite

Which two intestinal protozoans lack peripheral chromatin in their cyst forms?

Iodamoeba bütschlii & Endolimax nana

Amoebae stained with this substance may be readily distinguished, since it enhances nuclear and structural detail.

Iodine

A tech is interpreting a urine culture from a catheter as the source. There is 1 colony of Staphylococcus epidermidis present on the blood agar which was streaked with a 0.001 loop. What should the tech do next?

List S. epidermidis as a possible contaminant

A tech is interpreting a urine culture with a source of suprapubic aspiration. There is one colony of Staphylococcus epidermidis present on the blood agar which was streaked with a 0.01 loop. What should the tech do next?

List and provide a sensitivity for the S. epidermidis

A tech is working on a urine culture and finds the following isolate: Escherichia coli: 5,000 cfu/mL How should the tech continue with the culture work up?

List the E.coli as a possible contaminant

A 30-year-old Hispanic pregnant female developed fever and signs and symptoms of meningitis following ingestion of cheese sent by relatives in Mexico. The colonies recovered from a positive blood culture is shown in the upper photograph; the microscopic features in the lower photograph. The most likely identification is:

Listeria monocytogenes

A gram positive bacillus grew as a diffusely beta-hemolytic colony from a newborn. It was catalase positive and had tumbling motility on a hanging drop preparation. The image shows how the organism grew in the motility medium. What is the most likely diagnosis?

Listeria monocytogenes

An organism isolated from the spinal fluid of a newborn produced small, grayish, slightly translucent beta-hemolytic colonies on sheep blood agar. A Gram stain of the colony showed small Gram-positive rods that look like diphtheroids. The organism is MOST likely:

Listeria monocytogenes

Illustrated in the upper photograph to the right are small, gray-white to light yellow colonies surrounded by zones of beta hemolysis. Short, gram-positive bacilli with rounded ends that lie singly or in loose clusters are observed in gram stains. Two key identifying features, as illustrated in the lower photograph, are a narrow band of "umbrella" motility observed beneath the surface of semi-solid motility medium and the deep black slant of positive esculin activity. This species may be recovered during influenza-like infections during 2nd and 3rd trimester of pregnancy. With these observations, which of the following organisms is the identification of this isolate?

Listeria monocytogenes

Illustrated in this photograph to the right is a sulfide indole motility (SIM) tube (left) and an esculin hydrolysis slant (right) after inoculation with an unknown gram positive bacillus and incubation at 30°C for 24 hours. Based on the reactions observed, the most likely identification is:

Listeria monocytogenes

Observed in the top photographs are colonies growing on blood agar after 24 hours incubation, obtained from a positive blood culture. The colonies are tiny and surrounded by narrow zones of beta hemolysis. The initial presumptive identification was that of a Streptococcus and a CAMP test was set up. A follow up Gram stain (middle image) revealed Gram positive bacilli in loose clusters rather than cocci. The lower image demonstrates a rectangular zone of hemolysis in the CAMP test, compared to the arrow-head shape of a control Streptococcus. From these observations, select the most likely presumptive identification of this isolate.

Listeria monocytogenes

Of the organisms listed, which is most likely to be contracted following consumption of unpasteurized milk?

Listeria monocytogenes

The red arrow in the photograph is pointing to a typical arrowhead-shaped zone of hemolysis that is produced by Streptococcus agalactiae with the CAMP test. A beta-hemolytic Gram-positive bacillus that produces a rectangular-shaped area of hemolysis as shown by the blue arrow is:

Listeria monocytogenes

Which bacterial species is a common agent of neonatal bacteremia?

Listeria monocytogenes

Which organism matches the reactions shown? Left tube: Motility agar (note subsurface flare shown by arrows) Middle tube: Esculin hydrolysis (+) Right tube: Voges-Proskauer(VP) (+)

Listeria monocytogenes

What is the primary target of HBV?

Liver

Which organ is the primary target of the hepatitis B virus?

Liver

Illustrated in the image shown is the tail portion of an adult worm of a filarial nematode. These worms average 250 µm in length and commonly migrate through sub-cutaneous tissue, particularly in the thin skin below the conjunctival lining of the eye, resulting in a condition known as "Calabar swelling". What is the identification of this species that presents with nuclei seen in the tail section?

Loa loa

Which of the following organisms has been isolated from nasal secretions and causes atrophic rhinitis, a tissue-destructive disorder in the nose?

Klebsiella pneumoniae subsp. ozaenae

A quality control program is to be set up for the following tests: Phenylalanine deaminase (PAD)Indole productionVoges-Proskauer (V-P) Which pair of stock culture organisms would be most suitable to verify the performance of these three tests?

Klebsiella pneumoniae, P. vulgaris

Using molecular methods to identify organisms can provide GREATER specificity when compared to phenotypic methods. Which of the following organisms would molecular methods not be beneficial over phenotypic methods in identification?

Klebsiella species

An error is a verified and reported result on a patient that is later determined to be inaccurate. To identify an error, reports can be reviewed, other microbiologists may locate the error through testing, or nurses and physicians may come across the error when evaluating laboratory results. If an error is detected by repetitive quality control testing, which may indicate probable erroneous patient results, this is an example of which type of error detection?

Laboratory detection

From the choices listed below, which organism is classified as an aerotolerant anaerobe?

Lactobacillus species

Pictured are tiny, gray-white, non-hemolytic colonies growing on blood agar that are non-descript. The Gram stain reveals elongated, rectangular gram-positive bacilli in short chains. Key to the identification would be the lack of biochemical activity. This bacterium is usually recovered as a genital tract commensal, but has also been found to provide protection against other infective bacteria. With these observations, what is the most likely identification of the isolate?

Lactobacillus species

Small, smooth, gray-white, 24-hour colonies are seen growing on the surface of sheep blood agar with faint alpha-hemolysis. This isolate is most often part of the normal flora, serving in several body sites as a protection against harmful bacteria through production of lactic acid. The gram stain reveals long, slender gram-positive bacilli lying singly and in short chains. It is a non-branching, non-spore-former. From the multiple choices, select the presumptive identification of this isolate.

Lactobacillus species

The red/pink color of the colonies seen on this MacConkey agar plate is an indication of:

Lactose-fermenting gram-negative bacilli

A 10-year-old male presented to the local Appalachian Mountain clinic complaining of vomiting, fever, and severe abdominal pain. Patient history revealed that the child lives in the area in substandard conditions and receives only one balanced meal per day. A stool was collected and submitted for parasite study. This suspicious form, measuring 50 µm by 35 µm was found. This patient is most likely infected with:

Large intestinal roundworm

Consider the following characteristics of hookworm infection. Each is correct EXCEPT:

Larvae are carried in the blood to the bronchial tree where they mature in the lungs.

The cryptococcal antigen test used to diagnosis Cryptococcus neoformans meningitis is based on what type of rapid methodology?

Latex agglutination

The Knott technique serves as a means of identifying:

Loa loa

This parasite was observed in a stained blood smear and measured 260 µm in length with a sheath with nuceli extending into the tip of its tail. It is most likely which of the following?

Loa loa microfilaria

This medium is used for the cultivation and identification of Corynebacterium diphtheria. It contains serum and egg which stimulates growth and the production of metachromatic granules in the cells. Select this media from the following.

Loeffler medium

Which phase of the bacterial growth curve demonstrates the greatest growth activity?

Log phase

Performing quantitative cultures on bronchoalveolar lavage and protected brush specimens are better than performing routine semi-quantitative cultures because in quantitative cultures there should be which of the following?

Low numbers of contaminating normal respiratory flora and colonizing organisms and higher numbers of potential pathogens.

The anaerobe producing the double zone of hemolysis, seen in this photograph, can be presumptively identified as Clostridium perfringens. The enzyme producing the outer zone of hemolysis is:

Lecithinase

The beta hemolysis seen around the opaque, flat, spreading colonies illustrated in this photograph of a 5% blood agar plate is helpful in differentiating Bacillus cereus (hemolytic) from Bacillus anthracis (not hemolytic). Each of the following characteristics is also helpful in differentiating these two species EXCEPT:

Lecithinase production

All of the following colony and microscopic descriptions are paired correctly with the mold indicated, EXCEPT:

Macroscopic description: green, granular, rugose colonies Microscopic description: chains of spherical conidia produced from branching phialides Aspergillus sp.

All of the following are roles of a sentinel microbiology laboratory, EXCEPT?

Make the determination that a bioterrorist event has occurred

A gram-negative rod from a stool culture produces red colonies with black centers on xylose lysine decarboxylase (XLD) agar. When the organism is inoculated to triple sugar iron agar (TSIA) and lysine iron agar (LIA), it should appear as which of the sets of tubes shown in the image?

Left

Buffered charcoal yeast extract agar (BCYE) is the nonselective solid culture medium used for the primary recovery of:

Legionella pneumophila

The Gram stain of a sputum is unremarkable but the culture reveals many small gram-negative rods that are able to grow only on charcoal yeast extract agar. What is the MOST likely diagnosis?

Legionnaire's disease

Which of the following reside inside of macrophages, as depicted in the drawing to the right?

Leishmania amastigote

The suspicious form in this photograph was recovered from a bone marrow sample and measures 11 µm in length. What is the MOST likely identification of this organism?

Leishmania promastigote

Illustrated in the high power image is an inflammatory reaction of a skin lesion at the site of a Phlebotomus sand-fly bite. Observed are large histiocytes with small intra-cytoplasmic oval cells measuring 2 µm in diameter that superficially have the appearance of Histoplasma capsulatum yeast cells. Note the distinctive bar-like kinetoplasts that lie adjacent to the nucleus of some of these cells (arrows). Select the name of the protozoa.

Leishmania species

Which parasite corresponds with the sandfly as its insect vector?

Leishmania spp.

A 34-year-old female was seen in the dermatology clinic for some lesions on her fingers that had not responded to topical antimicrobial therapy. A tissue biopsy was sent for histological examination, routine culture, acid-fast bacilli (AFB) culture, and fungal culture. There was no growth on any culture, but AFB were seen in the histological preparations. The tissue culture for AFB had been incubated at both 35oC and 32oC, in liquid media and on media with hemoglobin added for several weeks. What is the most likely diagnosis of her skin lesions?

Leprosy

Illustrated in the upper image is a 4 day growth of a fungus colony on Sabouraud's dextrose agar. Note the cottony to woolly surface, and the distinctive lavender, pink pigmentation. The lower image is of a lactophenol cotton blue pigmented view of long, narrow multi-celled macro-conidia that are sickle-shaped. Based on these observations, select the genus identification of this isolate.

Fusarium

Which one of the following fungi is MOST likely to be seen in skin infection of burn patients?

Fusarium sp.

This rapidly growing hyaline fungus is the most common cause of Keratomycosis (an infectious disease of the cornea). The colonies can range in color from rose to mauve to orange. This organism is commonly recovered from blood and grows on sabourauds dextrose agar with brain heart infusion. The microscopic appearance shows abundant banana or canoe shaped macroconidia. What fungus causes this disease?

Fusarium species

Which of the following species or organisms is the most likely to cause mycotic keratitis (fungal infection of the cornea)?

Fusarium species

Which term describes the cellular morphology of bacteria with a pointed end?

Fusiform

Observation of colonies on KVLB agar producing chartreuse fluorescence under a Wood's lamp allows for presumptive identification of which anaerobic bacterial genus?

Fusobacterium

The colonies illustrated in the top photograph are 48-hour-old colonies growing on the surface of blood agar that had been incubated anaerobically. The colonies are small, gray-white and convex with irregular borders and internal flecking. Long, slender fusiform Gram negative bacilli with tapered ends are seen in the Gram stain as observed in the bottom photomicrograph. The indole reaction is strongly positive and glucose fermentation is variable; other biochemical reactions are negative except for H2S production by some strains. This isolate is commensal in the upper respiratory tract and has been associated with hospital acquired aspiration pneumonia, lung abscesses, and empyema in hospitalized patients. Based on these observations, select from the multiple choices the name of this isolate.

Fusobacterium nucleatum

The gram stain image on the right is a vaginal smear obtained from an 11-year-old girl suspected of being the victim of sexual abuse. The appearance of intracellular gram-negative diplococci (GNDC), as seen in the segmented neutrophil at the tip of the arrow, can represent different organisms. Therefore, recovery of the bacterial species in culture and biochemical identifications is needed before the case can be resolved. Each of the following may appear as intracellular GNDC EXCEPT:

Gardnerella vaginalis

Leuconostoc species are streptococcus-like bacteria used in the dairy and pickling industries that have recently caused opportunistic infections in humans. The need to make the laboratory identification is compounded because these bacteria are intrinsically resistant to vancomycin. Which characteristic is most helpful in separating Leuconostoc species from other streptococcus-like organisms?

Gas from glucose in MRS broth

Nocardia farcinica has been distinguished from other members of the Nocardia asteroides complex because most strains are resistant to several extended-spectrum antimicrobial agents and other antibiotics commonly used to treat nocardia infections, and are more commonly recovered from patients with severe underlying illness. Each of these characteristics are helpful in the identification of N. farcinica EXCEPT:

Gelatin hydrolysis

Illustrated in the top photograph is a 4-day-old white to cream-colored colony with a yeast-like background, but with the surface having a delicate silk-like consistency. Such colonies may be recovered as a contaminant in laboratory cultures. The identification is illustrated in a cornmeal agar mount shown in the bottom photograph. From these observations, the MOST likely identification of this yeast-like isolate is:

Geotrichum candidum

Blood cultures are collected from a septic patient with a history of chronic urinary tract infections. The sheep blood agar and the chocolate agar grow a creamy colony that has feet like or star like projections from the colony. The Gram stain of the colony demonstrates a budding yeast with pseudohyphae. What would be the next step in identifying the organism?

Germ tube

A large number of antigen detection procedures and assays are available to diagnose clinically suspected parasitic diseases in the absence of finding ova or other forms of parasites in stool preparations or other body fluids. Illustrated in the photograph are antigen positive-staining green dots at sites where small drops of duodenal aspirated fluid had been applied to the test reagents. Trophozoites of this protozoan occupy the upper gastrointestinal tract and the excreted ova may not find the way down the long stretch of bowel to be excreted in stool specimens. From the list of multiple choice selections, indicate the genus/species in which antigen detection may be required to make a diagnosis.

Giardia duodenalis

Illustrated in the photograph is a 15 X 25 µm trophozoite recovered from the stool specimen of a 30-year-old man with intermittent chronic diarrhea and malabsorption with onset 4 months after a camping trip to the nearby mountains. From the multiple choices listed, select the most probable presumptive identification.

Giardia duodenalis

Observed in the photomicrograph is an oval 10 µm cyst as observed in a mount of a third stool specimen prepared from a patient with intermittent diarrhea. Note the thin, smooth outer membrane. Two nuclei are observed within, with large, eccentrically placed karyosomes devoid of a chromatin ring. Four curved fibrils are also present. From the observation of this ova, select the presumptive identification.

Giardia duodenalis

The Entero-Test or string test may be helpful in diagnosing an infection with which of the following parasitic organisms?

Giardia duodenalis

The Enterotest may be used to recover which of the following parasites?

Giardia duodenalis

When parasites are observed in clinical stool specimens, antigen detection is the preferred method for identification, providing increased sensitivity over more common microscopy techniques. Several commercial products (DFA, EIAs, and rapid tests) are available. The H & E - stained tissue section of duodenum illustrates the presence of an intra-luminal intestinal trophozoite in which an antigen assay might be helpful in making a definitive identification. Select the presumptive identification from the choices listed.

Giardia duodenalis

A 35-year-old male presented to the local clinic complaining of abdominal cramps, severe diarrhea, and intestinal gas. A stool specimen was collected for parasite examination. It was foul-smelling and light colored in nature. The form in the attached image was recovered and measured 10 µm by 12 µm. The patient is infected with which of the following?

Giardia duodenalis (formerly lamblia)

The photograph demonstrates a microorganism detected in a stool sample submitted for ova and parasite examination. The organism measures 12 µm by 7 µm.

Giardia duodenalis cyst

Identify the parasite seen in the image that is sometimes found in stool as well as in duodenal contents. The organism in the image measures 15 µm in length.

Giardia duodenalis trophozoite

The 4-day old colony recovered on Sabouraud's dextrose agar, as illustrated in the top photograph. The specimen was taken from a skin infection incurred by a 45 year old farmer. The microscopic appearance, obtained from the surface mycelium of the colony, is illustrated in the lactophenol blue mount in the bottom image. What is the fungal isolate shown?

Microsporum gypseum

MIC is an acronym for:

Minimum inhibitory concentration

In the life cycle of the intestinal trematodes, Fasciolopsis/Fasciola and Heterophyes, which of the following is known to infect snails?

Miracidium

Which of the following steps is the first step of the ethyl acetate concentration procedure?

Mix fresh stool specimen with 10% formalin and strain to obtain a sediment

When performing sequence-based analysis to identify a bacterial isolate, all of the following must occur to ensure accurate results are obtained EXCEPT?

Mixed cultures can be used as specific sequence is being identified

Of the following organisms, which organism is known to cause bacterial vaginosis?

Mobiluncus species

Carbapenemases are produced by various organisms such as Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter species. Detecting the presence of carbapenemase activity in these organisms is important to prevent spreading of the resistant organisms. Which of the following methods is used to detect the presence of carbapenemase producing organisms?

Modified Hodge Test

Neisseria species can be traditionally differentiated by their fermentation of sugars. Identify the biochemical reaction that goes with the correct species of Neisseria given.

N. meningitidis = Glucose +, maltose +, lactose -

The nitrate reduction test is used to determine the ability of an organism to reduce nitrate. The Enterobacteriaceae group can reduce nitrate. Based on this test, what is the end product for which nitrate is reduced?

N2

Which of the following amoebae has a flagellate form as part of its life cycle?

Naegleria fowleri

Which of these parasites can be contracted by swimming in infected water?

Naegleria fowleri

Which organism is considered free-living amoebae?

Naegleria fowleri

Which of the following can be found in cerebral spinal fluid (CSF) and measures approximately 15 µm?

Naegleria fowleri trophozoite

Which of the following is the most suitable specimen for the isolation of Bordetella pertussis?

Nasopharyngeal swab

A 32-year-old male was seen in the emergency room with gastrointestinal discomfort. Upon questioning the patient it was learned that he first began feeling ill after spending a day at the park where he swam and played volleyball barefooted. He first noticed a lesion on his foot. Later, he developed vague respiratory symptoms. Now his largest complaint is severe abdominal pain along with occasional vomiting. This patient is most likely suffering from a parasitic infection with:

Necator americanus

On occasion in cases of heavy infection, rhabditiform nematode larvae, measuring up to 1.5 cm long, may be observed in mounts prepared from stool specimens. A presumptive species identification can be made by microscopically observing the buccal cavity as illustrated in the photograph. What is the most likely species of this nematode?

Necator americanus

The human infections related to the 60 X 40 µm ovum, as illustrated in the image, are reported by the World Health Organization to involve several million people worldwide. Symptoms vary from nausea and diarrhea in patients with light infection, to peripheral edema, anemia, dehydration, and congestive heart failure in those with heavy infections. Select the most likely genus/species identification.

Necator americanus

The colonies observed in the upper image on the right are non-pigmented and dry to chalky. They were recovered from an expectorated sputum sample of an immunocompromised 70-year-old man with pneumonia. The Gram stain shown in the lower image to the right depicts delicate, branching bacilli. Based on this information, what is the most likely identification of this pathogen?

Nocardia asteroides

All of the following statements about peptide nucleic acid-fluorescence in situ hybridization (PNA-FISH) are true for Staphylococcus EXCEPT?

PNA-FISH assays provide differentiation between Methicillin Resistant Staphylococcus aureus (MRSA) and Methicillin Sensitive Staphylococcus aureus (MSSA).

The fungal colony illustrated in the upper image was observed after 4 days incubation at 30oC and recovered from dialysis fluid of a 60-year-old patient who had been receiving multiple antibiotics for treatment of bacterial peritonitis. The lower image is of a microscopic view of a lactophenol blue stained mount taken from a small sampled of the surface of the colony. Note the distinctly pointed phialides from which long chains of small, spherical conidia are derived. What is the appropriate identification based on the colony morphology and microscopic features as observed in the lactophenol stained preparation?

Paecilomyces

Of the Enterobacteriaceae listed below, which of the following species fails to decarboxylate lysine, ornithine, and arginine?

Pantoea agglomerans

Identify the species of dimorphic fungi in its yeast form as observed under the microscope.

Paracoccidioides brasiliensis

The dematiaceous colony illustrated here grew to a diameter of 3 - 4 cm in 5 days. Which of the following fungi can be ruled out based on the information given?

Phialophora verrucosum

A bacterium was isolated as the cause of a urinary tract infection. The organism showed no lactose fermentation on MacConkey agar (MAC). On triple sugar iron (TSI) media, the organism produced an A/A with H2S. What organism is most likely observed?

Proteus vulgaris

Prior to receiving antibiotic therapy, a patient had a urinary tract infection with gram-negative, motile rods producing the following reactions: Indole: posH2S (TSI): posMR: posVP: negPhenylalanine deaminase: posUrea: posCitrate: posOrnithine decarboxylase: negGelatin hydrolysis: pos Based on the reactions above, what organism is MOST likely causing the infection?

Proteus vulgaris

The trichrome stain is most commonly used to identify which class of parasites?

Protozoa

Microorganisms that may be best visualized with Trichome stain (shown here) include: Image courtesy of CDC: https://www.cdc.gov/dpdx/diagnosticprocedures/index.html

Protozoan parasites

Sodium thiosulfate is often added to selective culture media to:

Provide sulfur atoms for H2S positive isolates

A member of the Enterobacteriaceae is inoculated into various biochemical media which are shown in the image. Shown from left to right are triple sugar iron agar (TSIA), lysine iron agar, urea agar, citrate agar, phenylalanine deaminase agar, and motility indole ornithine agar. This organism is most likely:

Providencia spp.

Select the most appropriate identification of a non-lactose fermenting Enterobacteriaceae based on the following test results: Indole positive TSI K/A H2S negative Citrate positive PDA positive Lysine decarboxylase negative Ornithine decarboxylase negative Urea negative The correct answer

Providencia stuartii

The following is true of the disk diffusion method of measuring antimicrobial sensitivity:

Provides only an interpretation value of sensitive, intermediate, or resistant correlated to MIC values

The following statements regarding the cell cytotoxicity neutralization assay (CCNA) for Clostridiodes (formerly Clostridium) difficile are correct EXCEPT?

Provides rapid results

When working up a culture, Scedosporium species may presumptively be identified if colonies have a "house mouse" gray appearance and microscopically observed are long delicate condiophores from the tips of which are produced a single oval conidium ("lollipop"). In some cases, further examination of the microscopic mount may reveal the branching, sheath-like arrangement (graphium form) of conidiophores as seen in the top image, and/or the spherical conidia-containing ascospores seen in the lower image. From the multiple choices, indicate the fungal species to be recognized.

Pseudoallescheria boydii

This gram stain smear was prepared from a sputum specimen and is viewed under oil immersion (1000X). What is the structure indicated by the arrow?

Pseudohyphae/yeast

A gram-negative rod isolated from a burn patient produced a bluish green pigment and the following test results: Characteristic fruity odorTriple sugar iron (TSI) agar: Alkaline/alkalineMotility: PositiveOxidase: PositiveOxidative/fermentation (OF) glucose: Oxidative utilization only What is the MOST probable genus of this isolate?

Pseudomonas

A 22-year-old construction worker incurred 3rd degree burns to the chest and arms when a boiler he was installing blew up. On the 5th hospital day the weeping wounds became infected, exuding what was described as green pus. The image illustrates the Gram stain prepared on a direct smear of the exudate. What is the MOST likely bacterial cause of the infection?

Pseudomonas aeruginosa

A flagellar stain would show peritrichous flagella for each of the following organisms except:

Pseudomonas aeruginosa

Each of the following organisms may possess extended-spectrum beta-lactamase (ESBL) activity except:

Pseudomonas aeruginosa

Exudate from a burn submitted on a swab for bacterial culture grew a gram-negative bacillus that was oxidase-positive, produced an alkaline slant and butt on TSIA, was resistant to numerous antibiotics, and produced a green, water-soluble pigment. This organism would be identified as:

Pseudomonas aeruginosa

The bacterial species, a typical colony of which is illustrated in this photograph, and a common bacterial cause of otitis externa, also known as "swimmer's ear", can be identified as:

Pseudomonas aeruginosa

The colonies shown in the blood (BAP) agar (upper) and MacConkey (MAC) agar (lower) biplate are a 24 hour growth from an aerobic blood culture bottle that became positive at 12 hours after inoculation. The appearance of the colonies on MAC agar rules out the following bacterial species:

Pseudomonas aeruginosa

Some strains of Group F Strep can carry the group A antigen, potentially leading to a false positive identification of group A, Streptococcus pyogenes. A spot test that is helpful in differentiating these two species and thus preventing a false report is:

Pyrrolidonyl-b-naphthylamide (PYR)

The appearance of the bacterial colonies growing on the surface of the Hektoen Enteric (HE) agar plate shown in the photograph to the right are consistent with all of the following bacterial species EXCEPT:

Shigella sonnei

This member of the Enterobacteriaceae is shown on triple sugar iron agar, lysine iron agar, urea agar, citrate agar, phenylalanine deaminase agar, and motility indole ornithine agar. The most likely identification would be:

Shigella sonnei

All of the following organisms can exhibit beta hemolysis, EXCEPT:

Shigella sp.

A day-care outbreak of diarrhea revealed an oxidase-negative, non-lactose fermenting, nonmotile, gram-negative rod. These characteristics presumptively indicate which organism?

Shigella species

Although some strains may possess K antigen, which member of Enterobacteriaceae is classified serologically by O antigen, because it lacks H antigen?

Shigella species

All of the following statements about blood cultures are correct, EXCEPT:

Since latex gloves are sterile, you may use your gloved finger without further preparation to feel the vein on a prepped arm before making the stick.

You are collecting a throat swab specimen from a child with a suspected streptococcal infection. Which of the following collection techniques will ensure that only the posterior pharynx is sampled with the swab?

Sit the patient in a well-lit area. Have the patient tilt his/her head back. Use a tongue blade to depress the tongue. Access the posterior pharynx without touching the tongue, inside of the cheeks, teeth, or uvula.

All of the following information should be included in a direct microscopic examination of a Gram stained culture smear report EXCEPT:

Size of bacteria

Which of the following is a selective medium for Campylobacter jejuni?

Skirrow agar

The Entamoeba histolytica trophozoite is usually characterized by the presence of the following:

Small central karyosome in the nucleus, ingested RBCs

While many isolates of this organism remain susceptible to penicillin, resistance is increasing in some areas due to the organism's altered penicillin binding proteins. In such cases, the recommended treatment is erythromycin or chloramphenicol. Which of the following organisms does this desribe?

Streptococcus pneumoniae

With the widespread use of the pneumococcal vaccine, there has been a decline in the incidence of community-acquired pneumonia by which of the following organisms?

Streptococcus pneumoniae

All of the organisms listed below are matched with the most likely clinical condition found in patients with that organism, EXCEPT:

Streptococcus pneumoniae - cellulitis

Complete hemolysis of sheep blood agar as demonstrated by the image below would be seen in which of the following catalase-negative isolates?

Streptococcus pyogenes

The bacterium in the image to the right is also referred to in the quote below, what is the identification of this bacteria? "If a pregnant woman be attacked by erysipelas of the womb, it is fatal." - Hippocrates

Streptococcus pyogenes

This image shows a gram-positive, catalase negative coccus on sheep blood agar (beta-hemolytic). Please note the reactions with bacitracin (A) and trimethoprim sulfamethoxazole (SXT) disks seen on the right side of the agar plate. On the left side of the agar, a beta lysin-producing Staphylococcus aureus is streaked perpendicular to the unknown organism. What is the presumptive identification of this organism?

Streptococcus pyogenes

Which statement about assays for the antigenic detection of both Clostridium difficile toxins A and B is TRUE?

The antigenic assays give rapid results.

Molecular methods offer improvements in sensitivity, but they are dependent upon what factor?

The availability of specific instrumentation

All of the following are primary routes of transmission for intestinal amoebae, EXCEPT?

The bite of an insect

An expectorated sputum specimen is received for culture at your laboratory. You are preparing to make slides and inoculate the media and are observing the gross appearance of the specimen. The specimen is a mixture of watery, bloody, and purulent material. Which area(s) of the specimen is most likely indicated for culture and slides?

The bloody and purulent areas of the specimen are most indicated for culture and slide preparation.

What is successful molecular identification of methicillin-resistant Staphylococcus aureus (MRSA) based upon?

The detection of the S. aureus genes (orfX, nuc, or coa) gene and the mecA gene.

A tech receives a call requesting an additional sensitivity test on a patient culture. What information should the tech document in the patient's work card?

The name of the person requesting additional testing

In this image is a quadrant plate containing brain heart infusion agar supplemented with 6 µg/mL of vancomycin. The right upper quadrant was inoculated with the test strain of Enterococcus faecium. The presence of growth in the inoculated quadrant indicates ___________?

The organism is resistant to vancomycin

All of the following are reasons why the 2009 H1N1 influenza pandemic propelled the development of molecular assays EXCEPT?

The pandemic created a shortage of cell culture materials.

Which of the following infections is caused by Chlamydia trachomatis?

Trachoma, a major cause of preventable blindness in the world.

Infections with Eikenella corrodens is associated with:

Trauma associated with human teeth

This suspicious form, found in stool, which measures 15 µm by 10 µm, is responsible for which of the following diseases?

Traveler's diarrhea

Illustrated in the photomicrograph is an H & E - stained section of skeletal muscle illustrating the larval form of an invading parasite (arrow). Humans become infected by ingesting raw or poorly cooked infected animal meat. An epidemic occurred in the 1800's during the North Pole expedition when explorers were eating the raw and undercooked meat of infected indigenous polar bears that they had killed for food. What is the species shown?

Trichinella spiralis

Ingestion of viable larvae in improperly cooked pork could lead to human infestations with which organism?

Trichinella spiralis

Microscopic examination of peripheral blood may be diagnostic for infection with each of the following parasites EXCEPT:

Trichinella spiralis

Which of the following helminths is a tissue nematode whose life cycle resides in a single host?

Trichinella spiralis

Which of the following parasites enters its host through ingestion of infected pork?

Trichinella spiralis

The microorganism in the photograph was detected in muscle tissue. The most likely identification is:

Trichinella spiralis encysted larva

This parasite, found in striated muscle, is responsible for which of the following conditions?

Trichinosis

The colony illustrated in the top image developed after 4 days of growth on Sabouraud's dextrose agar. Note the extension of the outer margin to the rim of the Petri dish. The bottom image 2 is a methylene-blue stained image of an inoculum obtained from the surface of the colony. From these characteristics, select the fungus genus from the multiple choices.

Trichoderma

The colony in the upper image developed after 4 days of growth on Sabouraud's dextrose agar. Note the extension of the outer margin to the rim of the Petri dish. The lower image is a methylene-blue stained inoculum obtained from the surface of the colony. From the choices of fungi, select the genus described.

Trichoderma

The arrows in the image on the right point to single, long, tapered phialides that extend laterally from either side of the hyphae. This microscopic presentation is an identifying feature of which fungi?

Trichoderma species

Which of the following parasites has the longest undulating membrane?

Trichomonas hominis

I am found in stool and measure 10 µm by 8 µm.

Trichomonas hominis trophozoite

The image shows a scavenger that lives in the mouth and measures about 10 µm. What is the identification of the organism?

Trichomonas tenax trophozoite

All of the following represents organisms with the appropriate specimen type for diagnosis EXCEPT:

Trichomonas tenax- vaginal secretions

A women presents to her physician with complaint of a foul smelling vaginal discharge. The following are reported from the submitted sample of the yellow vaginal secretion: Wet prep: Many WBCs seen, no Clue cells seen, microorganism (20µm) seen with jerky motility Vaginal pH: 6.0 Amine (Whiff) Test: Positive What is the most likely cause of this vaginal infection?

Trichomonas vaginalis

Direct microscopic examination of a wet preparation of vaginal discharge provides the simplest rapid diagnostic test for which of the following organisms?

Trichomonas vaginalis

Illustrated in the photomicrograph is a 10 µm in diameter, trophozoite observed in a trichrome-stained vaginal smear from a 39-year-old female experiencing a frothy vaginal discharge along with vaginal discomfort and pain on urination. What is the name of the invasive parasite?

Trichomonas vaginalis

Many organisms depicted as the image labeled 'B' were found in a urine specimen of a 28-year-old male that was tested as part of a routine physical examination. What is the identification of the organisms?

Trichomonas vaginalis

All of the following parasites are correctly matched with its respective primary symptom, EXCEPT:

Trichomonas vaginalis - diarrhea

Illustrated in the composite photograph is an inflammatory reaction of skin with erythema and micro-pustule formation, most consistent with a dermatophyte infection. The lactophenol blue mount was prepared from a 4-day old colony grown from the skin lesion as shown. The accompanying lactophenol blue microscopic mount illustrates small, spherical micro conidia arranged in loose clusters along the sides of thin hyaline hyphae. The species identification can be confirmed by the positive urease reaction as shown. What is the appropriate identification?

Trichophyton mentagrophytes

Illustrated in the top photograph is a 5-day culture on Sabouraud's dextrose agar obtained from a skin scraping specimen of a "ringworm" lesion from the groin of a 25 year old male. The appearance of a wine red pigment diffusing into the agar at the margins of a cottony white colony is distinctive. The accompanying microscopic features are observed in the accompanying lactophenol blue stained mount illustrated in the lower photomicrograph. From the multiple choices, select the species name of the fungal isolate as illustrated.

Trichophyton rubrum

The profusion of tiny microconidia lining up along the hyphae in this photomicrograph is characteristic of which of the following organisms?

Trichophyton rubrum

A pleural fluid specimen is received in the laboratory for aerobic culture. The specimen measures about 0.5 mL. How should the tech process this specimen for culture?

Use a sterile pipette and add a drop of fluid per agar plate

A tissue sample is received in the laboratory for routine aerobic culture. How should the tech prepare the sample for inoculation onto agar plates?

Use a tissue grinder to homogenize the sample

Regarding specimens for legal testing, which one of the following is false?

Use an alcohol prep pad when cleaning the phlebotomy site prior to collecting a blood alcohol specimen.

If you receive a transudate fluid for a Gram stain and bacterial culture, what is the ideal specimen preparation method for the bacterial culture?

Use centrifugation to concentrate the sample; then using the pellet to inoculate the media.

A tech in the laboratory receives a cerebrospinal fluid (CSF) culture for Gram stain and culture. What steps are needed for best slide preparation of the specimen?

Use cytocentrifugation to prepare slide

Each of the following practices will better ensure the successful recovery of Campylobacter jejuni from stool specimens except:

Use of selenite enrichment broth

What is the role of a sentinel laboratory within the Laboratory Response Network (LRN)?

Use standardized testing protocols to rule-out critical biological agents or refer them to one of the LRN reference laboratories for identification

Select from the multiple choices the specimen that is inadequate for the recovery of anaerobes and should be summarily rejected upon receipt in the microbiology laboratory.

Uterine cervical swab in Cary-Blair transport medium

Isolation and detection of Gardnerella vaginalis from vaginal secretions is improved by which of the following?

Utilization of human blood agar

Which of the following tests would you employ to examine a CSF for syphilis:

VDRL

A physician suspected that a young, sexually active woman had bacterial vaginosis. Which of the following specimen sources is the correct specimen of choice to support a bacterial vaginosis infection?

Vaginal

A methicillin-resistant Staphylococcus aureus was recovered from a wound infection. Which antibiotic would be used for treatment?

Vancomycin

Minimum inhibitory concentration (MIC) susceptibility tests should be performed against other beta lactam antibiotics for Streptococcus pneumoniae isolates from blood cultures and other sterile body fluids. The reason for this is due to an emerging resistance against penicillin and other beta lactam antibiotics. However, there is one antibiotic that is used to treat drug resistant Streptococcus pneumonia infections and MIC results should be questioned when a resistant susceptibility is found. Which of the following antibiotics does Streptococcus pneumonia still remain sensitive?

Vancomycin

All of the following viral causative agent and associated disease state combinations are correct EXCEPT:

Variola Virus: Polio

The end product of fermentative metabolism of the Escherichia, Salmonella, and Shigella genera is which of the following?

Various mixed acids

The photograph on the right illustrates an apparent tapeworm strobila in which the individual proglottids are more broad than long. What is the MOST likely identification?

Vegetable artifact

A woman came to see her physician as she was having vaginal/vulvar itching and some pain upon urination. To obtain a diagnosis of a yeast infection, which of the following is the test of choice?

Wet preparation

With which of the following conditions is this suspicious form associated?

Whipworm infection

Which of the following animals is a a likely source of human tularemia infections?

Wild rabbits

An 18 year old immigrant from the Philippines presented to the local clinic shortly after relocating to the United States complaining of fever and chills. Examination of the young adult revealed enlarged lymph nodes. Blood was drawn and submitted for culture and parasitic examination. The culture was negative. This suspicious form was seen on the Giemsa-stained blood smear. It measures 225 µm in length. This patient is most likely infected with:

Wuchereria bancrofti

Illustrated in the photomicrograph is the tail portion of an adult worm of a filarial nematode. Human infections with this nematode are more commonly found among those living in Southeast Asia, but may be observed in recent travelers there and to surrounding regions. These adult worms measure up to 300 µm, occupy lymphatic channels and may cause lymphatic obstruction. Varying degrees of fever and chills may be experienced. The species indicated in this exercise by the orientation of nuclei within the tail section (arrows), more commonly involves the lymphatics of the genital tract resulting in orchitis and hydrocele. From the nematode species listed below, indicate the most likely species identification.

Wuchereria bancrofti

Which parasite is transmitted via a mosquito bite?

Wuchereria bancrofti

A small gram-negative rod isolated from an eye grows on chocolate agar and it produces satellite growth around staphylococci colonies on sheep blood agar. The organism requires:

X factor and V factor

How would you classify the organism on this Gram stain?

Yeast

A Wright Giemsa stained preparation was made of a bone marrow aspirate. The photomicrograph is representative of what was observed in other fields of view. Note the clearing around the cells as indicated by the arrow. The preliminary laboratory report should read:

Yeast cells consistent with Cryptococcus neoformans

Assume you perform microbiology for an institution submitting surveillance cultures for MRSA. Which isolate should receive further workup to rule out methicillin (oxacillin) resistance?

Yellow colonies on Mannitol Salt agar; catalase-positive, coagulase-positive.

From the choices listed below, select the characteristic that would immediately rule out a presumptive identification of Mycobacterium tuberculosis:

Yellow pigmented colonies after exposure to light

A stool culture from a hospitalized patient produces the following characteristics: Gram-negative bacillusUrease positiveWeakly fermentativeTSI slant is A/A These reactions suggest that the organism is most likely:

Yersinia enterocolitica

An 8-year-old boy underwent a laparotomy for clinical signs and symptoms of acute appendicitis. Instead, the appendix did not appear inflamed, but the mesenteric lymph nodes were enlarged and edematous. The photomicrograph is a close-in H & E section of an area within one of the lymph nodes, showing hyperplasia and focal necrotizing inflammation. What bacterial species most likely causing this reaction?

Yersinia enterocolitica

In the following list of organisms, which organism is considered cryophilic (can grow as low as 4° C)?

Yersinia enterocolitica

Which of the following organisms causes disease by direct invasion of tissues?

Yersinia enterocolitica

This photograph is of an isolate from a stool culture on a 4-year-old child with gastroenteritis. The medium contains cefsulodin, irgasan, novobiocin, bile salts, mannitol, neutral red, and crystal violet. Further identification tests will most likely identify this isolate as:

Yersinia enterocolytica

Matrix-assisted laser desorption-ionization time-of-flight (MALDI-TOF) is used for identification of aerobic bacterial isolates on a urine culture bench. Upon placing the target into the MALDI-TOF instrument, no peaks were found on the quality control wells, but the patient isolates gave good identifications. What caused this issue?

Quality control organism was not added to the target wells

A tech is working on a urine culture and finds the following isolates: Escherichia coli: >100,000 cfu/mL Enterococcus faecalis: 50,000 cfu/mL Klebsiella pneumoniae: 30,000 cfu/mL How should the tech continue with the culture work up?

Quantitate culture and report as mixed urethral flora/contaminants

The test used for the identification of specific capsular serotypes of Streptococcus pneumoniae is:

Quellung

The core (genome) of the HIV virion contains:

RNA

HIV is known as a retrovirus because:

RNA is used as the template for DNA synthesis

Which one of the following tests should be used to monitor a patient's response to treatment for syphilis:

RPR titer

All of the following viruses are classified as retroviruses, EXCEPT?

Rabies virus

The OF dextrose activity is a key initial assessment in the presumptive identification of the nonfermentative gram negative bacilli. Which of the following bacterial species utilizes dextrose oxidatively? (yellow reaction in the open tube)

Ralstonia pickettii (formerly Burkholderia pickettii)

Illustrated in this photomicrograph of a gastric biopsy specimen are a few thin, curved and S-shaped bacteria (arrows). This picture is suspicious for Helicobacter pylori. An additional test helpful in confirming this identification is:

Rapid urease

Which of the following is the common name for Hymenolepis diminuta?

Rat tapeworm

The saying, "If it wasn't recorded, it never happened," holds true in the microbiology laboratory because accrediting agencies require that detailed and accurate records be maintained. All of the following are purposes of record retention within the microbiology laboratory EXCEPT?

Records are not important as computers store all the data

Which Enterobacteriaceae are non-lactose fermenters on MacConkey (MAC) agar, have green colonies with black centers on Hektoen enteric (HE) agar, and on xylose-lysine-deoxycholate (XLD) agar will have red colonies with black centers?

Salmonella spp.

Examine the KIA tube on the right in the image provided and determine which of the following organisms produces the biochemical reaction seen.

Salmonella typhi

Illustrated in this photograph are the biochemical reactions of an unknown bacterial species produced in Kligler Iron Agar, Sulfide Indole Motility agar, indole broth, Voges Prokauer broth and Simmons citrate. The bacterial species most likely producing the reactions seen here is:

Salmonella typhi

Consumption of undercooked poultry or the handling of reptiles could cause which of the following conditions?

Salmonellosis

The presence of two sporocysts each containing four banana-shaped sporozoites is characteristic of this organism; however, only oocysts with one sporocyst are typically seen in patient specimens. Which of the following organisms does this represent?

Sarcocystis species

All of the following are usually associated with Group A Beta Strep, EXCEPT?

Scalded Skin Syndrome

What is the proper method for examining a trichrome stained smear using bright field microscopy?

Scan the slide on low power (10X or 40X) first, then switch to oil immersion (100X) and scan the thin areas of the slide.

Illustrated in this photograph, reading from left to right, are tubes of Kligler Iron agar (KIA), Sulfide Indole Motility agar, indole broth, Voges Proskauer broth and Simmons citrate. The bacterial species most likely producing the reactions illustrated here is:

Shigella sonnei

Shigella serotyping is performed by using a polyvalent somatic (O) antisera. A Shigella species grew from culture and serotyped as Group D. Which of the following Shigella species serotypes as Group D?

Shigella sonnei

The fungal colony illustrated in the upper image, observed after 4 days incubation at 30°C, was recovered from dialysis fluid of a 60 year-old patient who had been receiving multiple antibiotics for treatment of bacterial peritonitis. The colony surface is cottony and green in pigmentation. The lower image is of a methylene-blue stained section of fruiting heads observed in a mount prepared from a small sample of the colony surface. Based on the colony morphology and microscopic features, what is the genus identification of this isolate.

Penicillium

The hyaline mold colony represented in the composite picture is approximately 8 days old. The most likely genus is:

Penicillium

Which of the following is a common contaminant that first rapidly produces white growth and then becomes powdery, bluish-green growth? The microscopic examination shows spore-bearing hyphae that characteristically form a brush with unbranched conidia arising from sterigmata that are arranged in whorls.

Penicillium

The trophozoite is the only morphologic form in the life cycle of:

Pentatrichomonas hominis

Illustrated in the upper photograph is growth of off-white, convex colonies with internal flecking after anaerobic incubation for 48 hours on anaerobic blood agar. Beta hemolysis is not observed. The colonies were recovered from a uterine cervix specimen obtained from a 30 year-old female with post-partum endometritis. The gram stain reveals small gram-positive cocci arranged in short chains and pairs. A spot indole and catalase test were negative. From these observations, select the presumptive identification of this isolate.

Peptostreptococcus anaerobius

Which of the following organisms appear Gram positive when using the Gram Stain?

Peptostreptococcus anaerobius

Which type of healthcare occupational exposure has the greatest risk of HIV transmission?

Percutaneous injury

All of the following are responsibilities of sentinel laboratories within the Laboratory Response Network (LRN), EXCEPT:

Perform full identification and susceptibility on all potential bioterrorism agents.

A tech is working on a urine culture and finds the following isolates: Escherichia coli: >100,000 cfu/mL Staphylococcus epidermidis: 5,000 cfu/mL How should the tech continue with the culture work up?

Perform sensitivity on E. coli and list the S. epidermidis as a contaminant

In the microbiology laboratory, four specimens are received at the same time. The specimen that should be processed immediately is:

Pericardial fluid

Which of the following conditions is a category B condition in a HIV-infected adult?

Peripheral neuropathy

Which site listed below should be accepted for a rapid strep screen?

Peritonsillar fossae

Which of the following describes the flagella on the bacterium in in image B?

Peritrichous

Enterococcus spp. are commonly resistant to all of the following antimicrobial drug types EXCEPT:

Phenicols

Illustrated in this image is the fruiting head of one of the fungal agents of chromomycosis. Note the long urn-shaped phialides tapered at the ends and topped with a distinctive flat, saucer shaped cap. Which of the following choices represents the type of sporulation illustrated in this image?

Phialophora sporulation

Which dematiaceous fungi affects the joints causing septic arthritis?

Phialophora spp.

All of the following are considered opportunistic pathogens EXCEPT:

Phialophora verrucosa

In observing the slow-growing, 7-day-old dark brown colonies growing on Sabouraud Dextrose with Brain Heart Infusion (SABHI) agar, note that the black pigment extends to the reverse of the colony. This provides a presumptive indication of one of the fungi involved in chromoblastomycosis. The species identification of this fungus can be made by observing the distinctive fruiting heads illustrated in the bottom image. Select the identification of the fungal species.

Phialophora verrucosa

The segmented, dark-staining grains seen in this photomicrograph are most commonly seen in cases of chromoblastomycosis. Which of the fungal species listed below is known to cause this disease?

Phialophora verrucosa

This organism is a slow-grower on Sabouraud Dextrose Brain Heart Infusion (SABHI) agar. It was recovered from a chronic recurrent cyst of the skin of the lower leg. The brown hair-like surface pigmentation appears brown-black when observed on the reverse of the colony. The identification is made by the microscopic appearance of fruiting heads. The image shows hyphae that are dark with flask-shaped phialides which form on the tips of the condiophores. What is the name of this fungus?

Phialophora verrucosa

Which of the yeasts listed below is commonly used in baking?

Saccharomyces cerevisiae

A yeast identification system gave a biotype number for an unknown isolate that did not differentiate between Candida tropicalis and Candida parapsilosis. This isolate could be identified as C. parapsilosis on a cornmeal agar preparation if it produced:

Sagebrush appearance with large hyphae; blastoconidia not characteristically present.

A blood culture yielded an organism with the following reactions: TSIA: K/A, gas (+), H2S (+) Citrate: Positive Indole: Negative Lysine: Positive Ornithine: Positive Motility: Positive Phenylalanine: Negative ONPG: Negative Urease: Negative What is the most likely identification of this organism?

Salmonella

The select reactions observed in the partial API strip illustrated in this photograph, reading from left to right, are: ONPG negative; arginine, lysine, and ornithine decarboxylases positive; citrate positive; H2S positive, and the remaining reactions negative. These reactions are most consistent with which bacterial genus?

Salmonella

On MacConkey (MAC) agar, an isolate from a stool sample produced clear, colorless colonies. On Hektoen enteric (HE) agar, colonies were green with black centers, indicative of H2S production. Additional biochemical tests were positive for methyl red, and negative for indole, VP, citrate, and PAD. From the choices listed, which species best matches the characteristics described?

Salmonella Typhi

Serological detection of the Vi antigen aids in identification of:

Salmonella Typhi

Lysine iron agar is a less commonly used culture medium that is most helpful in the identification of:

Salmonella enteritidis

History records an outbreak with the sudden onset of high fever, headache, and abdominal pain among 93 persons who had attended a public church dinner the week before. The photograph of an XLD agar plate is representative of the organism that may have been recovered from blood cultures from any one of these 93 persons. The most likely identification is:

Salmonella serotype Typhi

Which of the following Enterobacteriaceae produces H2S?

Salmonella species

This parasite, found in stool, measures 60 µm by 45 µm. Name that parasite!

Diphyllobothrium latum egg

Illustrated in the upper photograph image is an open segment of a surgically removed segment of small intestine on the surface of which are adult Cestode worms. The lower image is a view of a stained proglottid obtained from one of the adult worms. Based on the morphology of the proglottid, select the presumptive identification of the adult worms observed in this intestinal segment.

Dipylidium caninum

The eggs of this parasite arrange themselves in membrane-enclosed clusters known as packets:

Dipylidium caninum

The following cestode is commonly associated with dogs and cats but may also be transmitted to humans through the ingestion of dog and cat fleas that contain the cysticercoid of the parasite. Laboratory diagnosis may be made by observing groups of egg packets, as seen in the diagram, in the stool.

Dipylidium caninum

The packets of small, spherical immature ova (upper photomicrograph) may be observed in the ovaries of tapeworms indigenous in dogs and cats. Human infections are uncommon but on occasion stool specimens of young children with mild diarrhea who have had contact with household pets may include proglottids as represented by the lower photograph. Select the presumptive identification of this tapeworm from the multiple choice answers listed below.

Dipylidium caninum

Which of the following statements is true regarding the various non-molecular methods used for influenza testing?

Direct fluorescent antibody (DFA) staining on specimen smears can provide rapid results but are dependent on the availability of trained personnel to accurately interpret the smears.

The laboratory test most commonly used to establish a definitive diagnosis of primary syphilis is:

Direct fluorescent antibody test

A nasopharyngeal specimen is processed and fixed onto a microscope slide. Next, fluorescein-conjugated antibody is added to the slide. The specimen is incubated with the labeled antibody, washed, and then observed for fluorescence. Which of the following techniques best describes this process?

Direct immunofluorescence

Bacitracin susceptibility testing is useful for:

Distinguishing staphylococci from micrococci

What is a human infection caused by flukes called?

Distomiasis

The microbiology supervisor noticed that a higher number of RSV results were being reported on patients during a time when RSV infections are typically low. To determine the cause of the high number of positive results, the supervisor should perform all of the following EXCEPT?

Do nothing as RSV infections can occur at any time

The use of molecular testing to identify the presence of Methicillin-Resistant Staphylococcus aureus (MRSA) is not always the best method because false-positive results can occur. However, the main purpose for performing molecular testing on surveillance cultures for MRSA is all of the following, EXCEPT?

Does not require culture confirmation

Acceptable sources for urine culture from a patient with suspected urinary tract infection include all EXCEPT:

Drainage bag from nephrostomy catheter

A patient has a urinalysis performed and results are: Leukocyte esterase: Positive Nitrate: Positive What organism would the tech expect to find on the urine culture plates?

E. coli

Which of the following microorganisms is LEAST likely to produce a capsule or slime layer?

Escherichia coli

Which of the following organisms is the most common cause of acute cystitis?

Escherichia coli

Which of the following Mycobacterium species is positive for nitrate reduction?

Mycobacterium tuberculosis

Which organisms/conditions would be classified as Biosafety Level 3 agents?

Mycobacterium tuberculosis and Coxiella burnetti

Why is Mycobacterium tuberculosis not seen on gram stained smears?

Mycobacterium tuberculosis has a waxy coating on its surface which prevents gram stain penetration.

All of the following represent an area in clinical microbiology using molecular detection methods a routine diagnostic tool, EXCEPT?

Mycology testing

Which organism is a cell wall deficient bacterium that commonly causes primary atypical or "walking pneumonia?"

Mycoplasma pneumoniae

The "fried egg-like" growth - colonies with dense centers surrounded by a less dense periphery - seen here on PPLO agar is most likely caused by:

Mycoplasma sp.

Matrix-assisted laser desorption-ionization time-of-flight (MALDI-TOF) is used for identification of aerobic bacterial isolates on a urine culture bench. Upon placing the target into the MALDI-TOF instrument, no peaks were found on one of the patient samples (out of 20 patients). The quality control passed. What caused this issue?

Patient sample was not added to the well

All of the following patients may submit an urine specimen from an indwelling catheter EXCEPT?

Patient seen for an annual physical

Oxacillin resistance in clinical strains of staphylococci is confirmed by the detection of _______ gene.

mecA

Through the use of molecular assays, Mycobacterium tuberculosis (MTB) complex can be detected directly from respiratory specimens without being concentrated. In addition, due to rifampin resistance strains of MTB complex occurring, a genetic marker can be detected to identify rifampin resistance. Which of the following genetic markers is linked to MTB complex rifampin resistance?

rpoB gene

Molecular methods can identify the presence of methicillin resistant staphylococcus aureus (MRSA) in patient specimens by detecting different species-specific genes. All of the following are species-specific genes in detecting MRSA EXCEPT?

van A

Isolates of nonmotile and nonpigmented enterococci that are resistant to vancomycin can be assumed to have an acquired resistance by the transfer of which of the following genes?

van A and van B genes

Orthonitrophenyl-b-D-galactopyranosidase (ONPG) is produced by several bacterial species. It acts by cleaving the beta galactosidase bond of certain disaccharides, such as lactose. An ONPG-positive bacterial species, however, may appear as a "late lactose user" because of the absence of what?

ß-galactoside permease

Which of the following is a selective media recommended for the isolation of Clostridium difficile?

Cefoxitin-cycloserine-fructose agar (CCFA)

Which of the culture media listed is selective for the isolation of Yersinia enterocolitica in stool samples?

Cefsulodin-Irgasan-Novobiocin (CIN)

Various methods have been employed for detection of Clostridium difficile disease, which method is the gold standard for detection?

Cell cytotoxicity neutralization assay (CCNA)

In the image to the right, letter B represents what type of endospore placement?

Central

The laboratory receives a synovial fluid for acid-fast culture. How should the tech proceed with this culture?

Centrifuge the specimen and directly inoculate the culture

A large container of peritoneal fluid is received in the laboratory (about 50 mL). How should the tech process this sample for aerobic culture?

Centrifuge the specimen and use the sediment to inoculate the agar plates

All of the following life stages of schistosome worms are appropriately matched with the host they are found in, EXCEPT:

Cercaria - cow

Human infection of the Schistosomes occurs following penetration of what morphologic form into the skin?

Cercariae

Which of the following sample types should be processed first for a culture and Gram stain?

Cerebral spinal fluid (CSF)

Within the genus Campylobacter, the laboratory test most helpful in selectively identifying Campylobacter jejuni is:

Hippurate hydrolysis

From the fungi listed below, which is considered to be a true pathogen that also infects immunocompromised patients?

Histoplasma capsulatum

This suspicious form was found on a blood smear:

Artifact

What is this suspicious form seen in this photo from a stool sample that measures 10 µm in diameter?

Artifact

Which of the following is MOST often determined to be the cause of sepsis?

Bacteria

All of the following statements are associated with MALDI-TOF mass spectrophotometry used in clinical microbiology, EXCEPT?

Bacteria is amplified using a laser.

The optimum time to collect a urine sample to maximize recovery of the ovum illustrated in this iodine-stained mount of urine sediment is:

Between 10:00 A.M. and 2:00 P.M

All of the associations listed below between bacteria and their expected colony morphology on 5% sheep blood agar are correct, EXCEPT:

Escherichia coli - pink colonies

The following test may be performed on all swarming Proteus species to differentiate between Proteus mirabilis and Proteus vulgaris:

Indole

In the formalin-ethyl acetate sedimentation procedure, four layers will occur. Out of the layers, where does the formalin layer occur?

Between the bottom layer and the debris/fat layer

Procedures that may enhance the recovery of Streptococcus pyogenes from throat cultures include:

Incorporation of sulfamethoxazole and trimethoprim in the culture media

Which of the following would be the most appropriate temperature for long term storage of specimens for viral culture?

-70° C

Which of the following is used to standardize the bacterial inoculum used in a disk diffusion test (Kirby-Bauer method)?

0.5 McFarland standard

With regard to blood cultures, which blood to broth ratio is most conducive to growth?

1 : 10

If a Brucella species is suspected in a blood culture, it should be held for a maximum of how many days on a commercial blood culture system?

10-14

A patient was screened for possible methicillin resistant staphylococcus aureus (MRSA) by culturing the nares of the patient. All of the following media can be used to screen for MRSA EXCEPT?

Columbia agar

A clean catch urine was streaked to a sheep blood agar plate and a MacConkey plate with a one microliter (0.001 mL) loop. The images to the right demonstrate the observed growth. How would you report the colony count and growth?

10^3 CFU/mL of a gram-negative bacillus

The recommended temperature/time/pressure for routine steam sterilization of media is:

121° C for 12-15 minutes @ 15 psi

Which of the following HPV types are most likely to be associated with cervical cancer?

16 and 18

When identifying Mycobacteria by molecular methods, the most reliable gene sequence is:

16S

Sequence-based analysis is an alternate method used to identify bacteria and fungal isolates. This methodology uses rRNA genes (rDNA) and their intergenic regions as common target sites to identify these organisms. Which of the following rRNA gene target sites is used to identify bacterial isolates?

16S rRNA

The photograph illustrates a classic case of scrofula infection, most commonly caused by Mycobacterium scrofulaceum. The age range when this condition is most likely to appear is:

18 months-7 years

The minimum time of retention for microbiology test reports is?

2 years

When collecting specimens for viral studies, samples should be collected within how many days of symptom onset for best sensitivity?

2-3 days

The subsurface umbrella-shaped zone of motility seen in this SIM tube (arrow) is characteristic of Listeria monocytogenes. The optimum temperature of incubation to best illustrate this property is:

25°C

Sequence-based analysis is an alternate method used to identify bacteria and fungal isolates. This methodology uses rRNA genes (rDNA) and their intergenic regions as common target sites to identify these organisms. Which of the following rRNA gene target sites is used to identify fungal isolates?

28S rRNA

From the list of incubation temperatures, select the one that is currently recommended as a routine temperature of incubation for the laboratory recovery of fungi from culture specimens, being both successful and cost-effective.

30°C.

Within what period of time after performance of the tuberculin skin test (TST) should the result be read?

48-72 hours

Which culture agar combinations below will be MOST sufficient for routine urine culture investigations?

5% sheep blood and MacConkey

When a lumbar puncture is performed, what volume of spinal fluid is needed for optimal recovery of meningitis causing organisms?

5-10 mL

Which of the following is the correct order when performing a permanent stained smear of a stool specimen?

70% ethanol/D'Antoni's iodine; 70% ethanol; Trichrome stain; 90% ethanol;100% ethanol; Xylene

If a blood agar plate and an EMB plate are both inoculated with 0.001 mL of urine, and 90 colonies of Staphylococcus aureus grew on the blood agar plate, what should be reported?

90,000 colony forming units/mL of Staphylococcus aureus

When performing quantitative cultures from protected brush specimens, which of the following colony forming units per milliliter indicates a true bacterial pneumonia?

>103 colony forming units/mL

When performing quantitative cultures from bronchoalveolar lavage specimens, which of the following colony forming units per milliliter indicates a true bacterial pneumonia?

>104 colony forming units/mL

Presumptive identification of a bacterium may be suspected from observing the colony morphology of growth on blood agar. Please identify which photo (A, B, C, or D) matches the colony morphology closely resembling Proteus spp.

A

The fungus illustrated in this photomicrograph was recovered from an induced sputum specimen from a 74-year-old man with chronic obstructive pulmonary disease. This isolate is most likely:

A contaminant

The dark brown, wooly to velvety surface of the colony shown in the image to the right suggests a dematiaceous fungi. What additional feature would suggest recovery of one of the agents of chromomycosis, rather than one of the phaeohyphomycetes?

A delay in growth beyond five days.

Which of the following describes a sentinel laboratory as part of the Laboratory Response Network (LRN)?

A laboratory that performs basic testing to rule out possible bioterrorism agents, and then refers any suspicious agents or specimens to an LRN reference laboratory

All of the following are included in a standard ova and parasites examination, EXCEPT:

A parasite culture

The fever and chills syndrome associated with malaria is known as:

A paroxysm

The upper photomicrograph illustrates a Gram stain of sputum obtained from a 55-year-old man with symptoms of bacterial pneumonia. The lower photograph represents the growth of an inoculum from the specimen on 5% sheep blood agar, on which had been placed an optochin ("P") and a 1 µg oxacillin disk. After 18 hours incubation at 37°C in 5% CO2, the zone around the optochin disk is 18 mm and around the OX disk is 8 mm. The interpretation is that the organism is most likely:

A pneumococcus, penicillin resistant

The pathogenicity of Staphylococcus aureus, as well as the frequency with which this organism produces infections, can be attributed to all of the following EXCEPT:

A porous cell wall

Consider the following regarding infection with Mycobacterium tuberculosis. Each response is correct EXCEPT:

A positive purified protein derivative (PPD) test always indicates the presence of active tuberculosis disease.

Leading causes for laboratory rejection of a specimen include the following reasons EXCEPT:

A printed label is placed on the tube or container after specimen collection

The positive oxidase reaction as shown in the image (yellow arrow) rules out which of the following "look-alike" bacteria that resemble N. gonorrhoeae?

Acinetobacter baumannii

All of the following aerobic agars can be set up along with the anaerobic media, EXCEPT?

Columbia colistin-nalidixic acid agar

An Enterobacteriaceae grows as a clear colony on MacConkey but a salmon-colored colony with a black center on Hektoen enteric agar. Which of the following TSI reactions would match these morphologies?

A/A H2S

Referring to the image on the right, what is the correct identification for each egg?

A: Trichuris trichiura egg B: Hookworm egg C: Enterobius vermicularis egg

Illustrated in the photomicrograph are acid-fast stained mounts of a 5 µm oocyst of Cryptosporidium (top) and a 10 µm oocyst of Cyclospora (bottom). Knowing the clinical suspicion of what disease would alert the laboratory scientist that a preparation of an acid fast stain should be made on the submitted stool specimens?

AIDS

Which two of the following tests are helpful for documenting previous streptococcal throat and skin infections?

ASO titer & anti-DNase B

The spherical, finely-spiked macroconidia of Sepedonium species appear similar to those microscopically seen in the mold form of Histoplasma capsulatum. By what characteristic may Sepedonium be excluded?

Ability to produce yeast conversion when colonies are incubated at 35 - 37 degrees C

A 40-year-old man with a prosthetic valve developed intermittent bouts of low grade fever. A changing cardiac murmur suggested the possibility of endocarditis; however, repeat blood cultures over a two week period were all negative. Bacteria resembling those seen in the lower image were finally seen in Gram stain of a positive bottle. Colonies were recovered when broth was subcultured to a blood agar plate with a staph streak, as shown in the upper image. What is the most likely bacterial species?

Abiotrophia defectiva

Which of the following best describes the size and staining characteristics of yeast cells on a Gram stain?

About the same size as red blood cells and stain purplish-blue.

All of the following are collected from sterile sites, EXCEPT:

Abscess fluid

When an unknown member of the Enterobacteriaceae family is recovered in primary culture, which key characteristics would lead you to suspect Klebsiella pneumoniae?

Absence of motility

The border to border extension of the mycelium as illustrated in the top photograph is characteristic of one of the Zygomycetes. Although a light yellow green pigmentation of the mycelium is observed, the identification of the isolate depends on the presentation of the fruiting body observed in the bottom photomicrograph. From these observations, select the name of this isolate from the list of multiple choices.

Absidia species

A specimen suspected of containing which organism may be cultured by placing it on an agar plate with an overlay growth of Escherichia coli?

Acanthamoeba species

Of the protozoa listed below, which of the following can be routinely cultured?

Acanthamoeba species

The parasitic form shown in the illustration may be found in the eye, as a cause of keratitis. It measures approximately 25 µm in diameter. What is the identity of this parasite?

Acanthamoeba species

Thorn-like pseudopods are characteristic in trophozoite form of which amoeba?

Acanthamoeba species

If a Mycobacterium sp. infection is suspected on a bone marrow or body fluid, what stain should be used to detect these bacteria?

Acid fast stain

A modified acid-fast stain was used to produce the image on the right. What is the appropriate interpretation?

Acid-fast positive

What is the first test always performed on organisms growing on solid or liquid mycobacterial media?

Acid-fast staining

Direct Gram stain from a peritoneal fluid specimen appeared as Gram-positive cocci. After 24 hours, clear, convex, entire colonies grew on blood agar and faint lavender colonies were noted on MacConkey, grown aerobically. Gram stain was repeated and appeared as Gram-negative coccobacilli. The isolate was oxidase negative, catalase positive, non-motile, and resistant to penicillin. What is the presumptive identification?

Acinetobacter baumannii

Illustrated in the upper composite photograph are non-hemolytic, smooth, entire non-pigmented white colonies growing on blood agar. Human isolates are most commonly from nosocomial infections related to endotracheal tubes and tracheostomies, with peritonitis in patients receiving peritoneal dialysis. Distinctly light lavender-pink pigmented colonies are observed growing on MacConkey agar. Tiny coccobacilli simulating those of Neisseria species are observed in gram stains as illustrated in the lower photomicrograph. Other identifying features include the oxidative production acids from most carbohydrates (saccharolytic) and a negative oxidase test. From these observations, select from the multiple choices the presumptive identification of this isolate.

Acinetobacter baumannii

The bacterial species growing on the surface of the MacConkey agar plate shown in this photograph, a coccobacillary non-fermenter and a common cause of nosocomial hospital-acquired pneumonia, can be presumptively identified as:

Acinetobacter baumannii

The growth on a blood agar plate as illustrated in the photograph was prepared from the surface drainage of a subcutaneous abscess of a 50-year-old man following a deep penetrating splinter wound. The colonies on this young culture are small, rough, gray-white, and non-hemolytic. Older larger colonies became sunken centrally having a "molar tooth" appearance. The Gram stain reveals gram-positive branching filaments. Key biochemical reactions include hydrolysis of Esculin, nitrate reduction, and negative catalase. From these observations, select from the multiple choices the identification of this isolate:

Actinomyces israeli

A 49-year-old farmer developed swelling of the neck beneath the left jaw with enlargement of the left posterior cervical lymph nodes. The photograph to the right is representative of a direct gram stain prepared from purulent material aspirated from one of the enlarged lymph nodes. The organism was not acid fast. What is the MOST likely identification?

Actinomyces israelii

Gas-liquid chromatography is useful in the identification of anaerobes in addition to Gram-stain morphology. Which anaerobe produces succinic acid in abundance?

Actinomyces israelii

Which Gram positive bacilli will show a positive result for urease?

Actinomyces naeslundii

All of the following organisms stain with an acid-fast stain, or one of its variants, EXCEPT?

Actinomyces spp.

The organism depicted in the image to the right is found as normal flora of the mouth, GI, and genital tracts; it is known to cause a chronic disease that exhibits abscesses, tissue fibrosis, and draining sinuses. What is the name of this chronic disease?

Actinomycosis

A 36-year old woman is a known intravenous drug abuser, and gives a history of "several previous episodes of hepatitis". The laboratory workup is as follows:HBsAg- Reactive anti-HBs- Negative anti-HBc- Total Positive anti-HBc IgM- Negative anti-HAV- Total Positive anti-HCV- Positive anti-HAV IgM- Negative Which of the following diagnoses can be EXCLUDED based on laboratory data and current symptoms and history?

Acute hepatitis A

The bacterial species represented by the positive test illustrated in the photograph of a 5% sheep blood agar plate cross streaked with a hemolytic strain of Staphylococcus aureus has been associated with each of the following conditions except:

Acute post-streptococcal glomerulonephritis

A clean-catch midstream urine specimen from a woman was sent to the microbiology laboratory for culture. The patient had a history of dysuria, frequent urination, suprapubic pain, no fever, no flank pain, or any urinary symptoms in the last 4 weeks before her current episode. The urine grew out 1,000 cfu/mL of Escherichia coli. Which of the following categories would the patient be classified?

Acute, uncomplicated UTI in women

What are the four nitrogenous bases that are found in RNA?

Adenine, guanine, cytosine, and uracil

All of the following viruses have RNA as their nucleic acid content, EXCEPT:

Adenovirus

Which of the following describes a cestode?

Adults are ribbonlike and contain segments

The orgCamper/hiker outbreakanism Acinetobacter baumannii is known to have caused which of the following outbreaks?

Afghanistan and Iraq U.S. soldiers outbreak

Observations that can be made based on the Gram stain examination include all of the following, EXCEPT:

Age of the organism

Dematiaceous molds can be broadly separated into two major groups; the agents of chromomycosis and clinically insignificant commensals or contaminants. Which of the statements below is true?

Agents of chromomycosis grow more slowly than clinically insignificant commensals or contaminants.

The bacterial species commonly found in association with deep tissue actinomycosis is:

Aggregatibacter actinomycetemcomitans

The colonies illustrated in the upper photograph were recovered from the aspiration of nasal secretion from a patient with acute sinusitis. The 48 hour colonies on blood agar are relatively small, entire, white, and non-hemolytic. Colonies growing on chocolate agar are also small, smooth and entire with a light yellow pigmentation. On Gram stain, pale-staining, Gram negative coccobacilli are observed, with a tendency to form long, narrow filaments. The lower photograph reveals tube reactions with a KIA: Acid/Acid and the oxidative utilization of several carbohydrates except xylose and mannose. Nitrate reduction is positive and ornithine and arginine decarboxylases are negative. From the observations, select from the multiple choices the genus/species name of this isolate.

Aggregatibacter aphrophilus

Mycobacterium tuberculosis can be spread from person to person via which transmission method?

Airborne

How are the bacterial organisms that cause tuberculosis (Mycobacterium tuberculosis) primarily transmitted?

Airborne droplets/aerosols

All of the following are considered a potentially infectious body fluid or a route of transmission for HIV, EXCEPT?

Airborne transmission

Illustrated in the image to the left are 3-day old colonies growing on blood agar. The colonies are gray and spreading, and a sweet, fruity odor is noted. Plump, Gram-negative coccobacilli are seen on Gram stain. This isolate belongs to the motile, non-fermenters with peritrichous flagella. Carbohydrate utilization is asaccharolytic. Nitrite reduction produces gas and citrate is positive. From the multiple choices, select the name of this isolate.

Alcaligenes faecalis

Bacterial colonies often emit distinct odors associated with foods. Which organism produces an odor that resembles fresh apples?

Alcaligenes faecalis (odorans)

From the choices listed below, select the biochemical reaction that excludes a bacterial isolate from the family Enterobacteriaceae.

Alk/Alk reaction on Kligler's Iron Agar

Pseudomonas aeruginosa is often used as a bacterial species for the quality control of Kligler Iron Agar (KIA). The expected reaction is:

Alkaline slant/alkaline deep

Pseudomonas aeruginosa is often used as a bacterial species for the quality control of Kligler iron agar. What is the expected reaction?

Alkaline slant/alkaline deep

With regards to identifying resistance in Enterococcus species, all of the statements below are true, EXCEPT:

All antibiotics on a gram-positive panel should be reported.

This suspicious form, that measures 25 µm, was recovered in an eye sample. It is associated with which of the following diseases?

Amebic keratitis

Naegleria fowleri is associated with which of the following diseases?

Amebic meningoencephalitis

Where can sentinel laboratory staff find the standardized testing protocols?

American Society for Microbiology (ASM) website

Pseudomonas aeruginosa was isolated from a sputum specimen. Susceptibility testing was performed and the microbiologist determined that further evaluation needed to take place before reporting out the susceptibilities. Which of the antibiotic results would indicate that further evaluation needed to be taken?

Amikacin resistant, Gentamicin or tobramycin sensitive, Carbapenem resistant

A patient is being treated with gentamicin for a Gram negative bacterial infection. The chemistry department has repeating peak and trough orders on the patient. Which of the following antibiotic classes does gentamicin belong?

Aminoglycosides

Which of the following antibiotics inhibits protein synthesis by binding to the 30S ribosomal subunits and provides coverage against Gram positive and Gram negative aerobes?

Aminoglycosides

In the microbiology laboratory, the following specimens are received at the same time. Which specimen is classified as a level 1 specimen, requiring immediate processing?

Amniotic fluid

The image to the right is a picture of parasites. Which of the following does Image A represent?

Amoeba

A budding yeast with pseudohyphae and clusters of gram positive staphylococci were observed in a Gram stain smear prepared from a positive blood culture. What is the MOST likely source of the infection?

An indwelling catheter

The clinical Gram stain taken from an endocervix revealed many WBC's with both intracellular and extracellular gram-negative diplococci. The specimen was plated onto a Modified Thayer-Martin plate and incubated. Following incubation, colonies resembling Neisseria gonorrhoeae were inoculated into separate CTA tubes containing glucose, lactose, sucrose and maltose. The fluorescent monoclonal antibody test was positive as well as the CTA maltose and glucose tubes. What is the most appropriate next step?

Analyze another maltose tube using a known strain of Neisseria gonorrhoeae

Identify the species associated with the parasitic forms found in a stool specimen, as illustrated:

Ancylostoma duodenale

The eggs of Necator americanus are basically indistinguishable from the eggs of:

Ancylostoma duodenale

The laboratory diagnosis of this nematode is most commonly made by observing the characteristic eggs in stool specimens. On occasion, adult worms may be observed in the intestine, anchored to the mucosal lining in specimens that have been surgically resected or at autopsy. Illustrated in the photograph is the mouth part as observed in one of these adult worms. From the list below, select the most likely presumptive identification.

Ancylostoma duodenale

Which of the following is only observed in Salmonella infections and not in Shigella infections?

Animals serve as a reservoir of infection.

Which of the following arthropods are an important part of the life cycle of Plasmodium species?

Anopheles

A tech receives a request for MRSA/MSSA colonization testing on a patient in the hospital. Which of the following is an appropriate area of the body for culture for screening?

Anterior nares

Which of the following is necessary to test for in order to detect patients in the "window" period of a hepatitis B infection?

Anti-HBc

Which of the following assays should be performed after a specimen is shown to contain HIV antibodies when tested with a 4th generation HIV-1/HIV-2 antibody immunoassay?

Antibody immunoassay to differentiate HIV-1 and HIV-2

Septic arthritis can be caused by Neisseria meningitidis, Streptococcus pyogenes, and Streptobacillus moniliformis. Diagnosing these organisms from joint fluid can be difficult because they may not grow in culture. Which of the following contributes to the cause of non-culturable septic arthritis?

Antigen/Antibody complexes accumulate in the joint

Which of the following is used to determine if a person has had a recent infection with Strep pyogenes?

Antistreptolysin O (ASO)

Illustrated growing on the surface of the blood agar plate shown in the upper left image are small distinctly beta hemolytic colonies suggestive of beta hemolytic streptococci, particularly when specimens are obtained from patients with an upper respiratory infection. Gram-positive bacilli in branching and Chinese letter formations are observed on Gram stain as illustrated in the upper right image. Observe the reverse CAMP reaction in the lower image. From these observations, select the identification of this bacterial isolate.

Arcanobacterium haemolyticum

In patients who present with a classic "strep throat", the beta-hemolytic, catalase negative, Gram positive bacillus that must be included in the differential diagnosis is:

Arcanobacterium haemolyticum

The colonies growing on the surface of this 5% sheep blood agar plate, with ß-hemolysis, were recovered from a throat swab of a 19-year-old girl with acute pharyngitis. Gram stain revealed club-shaped Gram positive bacilli with rudimentary branching. What is this species?

Arcanobacterium hemolyticum

Based on the following choices, which one is the best way to identify microfilariae?

Arrangement of nuclei; presence or absence of a sheath

An 18 year old female athlete, who recently competed in a barefoot run for charity in Southern Georgia, presented to her doctor for a routine check-up. Other than complaining of being exhausted and having occasional diarrhea, she was in good health. The doctor ordered a stool for culture and parasite examination. The culture was negative. Numerous suspicious forms as shown in the attached image were seen upon microscopic examination of the stool. The most likely identification is:

Artifact

Identify this form found in a stool sample:

Artifact

Illustrated in the image shown is a 60 µm in diameter ovum that was observed in a diarrheal stool specimen obtained from a middle-aged male immigrant from Nigeria. He had suffered mild eosinophilic pneumonia a month before. What is best presumptive identification for the organism?

Ascaris lumbricoides

Illustrated the upper photograph is an adult 25 cm long nematode worm as it may appear in the intestine. In the lower is the associated 50 µm ovum that may be observed in stool specimens. From the list of organisms, select the name of the nematode represented by these images.

Ascaris lumbricoides

Identify the suspicious form (shown in the image) found in a stool specimen, measuring 50 µm.

Ascaris lumbricoides egg

The image to the right represents an egg that was found in stool and measures 55 µm. Which of the following parasitic eggs does this image represent?

Ascaris lumbricoides egg

This parasitic form, shown in the image to the right, was found in a stool specimen and measured 85 µm in length.

Ascaris lumbricoides egg

This suspicious form shown here at both low (10X) and high dry (40X) power, was seen in a stool sample. The form measures 90 µm by 42 µm. This form is most likely a _________?

Ascaris lumbricoides egg

This suspicious form, shown below at both low (10X) and high dry (40X) power, measures 90 mm by 42 mm. It was seen in a stool sample.

Ascaris lumbricoides egg

What is this form, measuring 45 µm and found in stool?

Ascaris lumbricoides egg

What is the phenotypic property of Saccharomyces yeast species that is helpful in establishing its species identification?

Ascospore production

The fungal colonies illustrated on the left image grew to maturity in 4 days. The isolate was recovered from the expectorated sputum of an elderly immune-compromised patient. The image on the right is the microscopic appearance of a lactophenol cotton blue stained mount prepared from a small sample from the surface of the colony. Note that microscopically the entire surface of a smooth spherical vesicle is surrounded by a row of phialides giving rise to small conidia.

Aspergillus flavus

A KOH mount is used to detect which of the following microorganisms?

Aspergillus fumigatus

The 4 day growth of colonies on Sabouraud's dextrose agar, as shown in the upper image, was recovered from the alveolar lavage of a 45 year-old construction worker who presented with X-ray evidence of a lung abscess. The light green colony in the upper image, with a cottony surface, shallow rugae, and a white surrounding apron was recovered on Sabouraud's dextrose agar from an induced sputum sample after 4 days incubation at 30° C. The Lacto-phenol cotton blue stain microscopic appearance from the surface colony is illustrated in the lower image. From these observations select the fungal species.

Aspergillus fumigatus

Which Aspergillus species has been recovered from the cornea?

Aspergillus fumigatus

A beta-hemolytic Streptococcus was isolated from a throat culture. It gave the following biochemical reactions: Bacitracin - Susceptible Bile esculin - Negative 6.5% NaCl - No growth CAMP - Negative SXT - Resistant What is the presumptive identification?

Beta hemolytic Streptococcus, Group A

Which of the following enzymes, produced by Staphylococcus aureus is responsible for preventing penicillin antibiotics from being effective?

Beta-lactamase

Which of the following instrument-based systems are considered a continuous monitoring system?

BACTEC

What biosafety level (BSL) is required by the Centers for Disease Control and Prevention (CDC) for working with Mycobacterium tuberculosis, if there is a possibility that aerosols might be released?

BSL-3

This organism is found endemically on the New England seacoast. When seen in peripheral blood smears, it resembles a parasite of the genus Plasmodium. When an organism resembling malarial parasites is found in the peripheral blood, it is most probably:

Babesia

The photomicrograph shows a close view of erythrocytes three of which are infected. The smear was obtained from a 40-year old forester working in Connecticut who was complaining of malaise and fatigue. Which of the following is the most likely identification?

Babesia microti

Which of the following parasites has a life cycle that most closely resembles that of Plasmodium species?

Babesia microti

Which of the following parasites have a life cycle that resembles that of the Plasmodium species?

Babesia microti

A laboratory recently purchased a continuous monitoring system for blood culture analysis. The system is able to detect CO2 production by growing organisms and as a result will produce a color change in the sensor located at the bottom of the blood culture bottle. The instrument will detect this color change and alert the staff that a blood culture is positive for bacterial growth. Which of the following instruments uses this methodology?

BacT/ALERT

It is important to make a presumptive identification of the large, flat, spreading, gray-white, non-hemolytic colonies, with comma-like extensions growing on blood agar, as illustrated in the upper photograph. When mucoid colonies are observed, peak-like extensions may be observed when the colony is lifted with an inoculating loop (lower left image in the composite). Long, spore-bearing, Gram positive bacilli, often in straight and branching chains, are observed on Gram stain. Based on the results given, select the presumptive identification of this isolate.

Bacillus anthracis

Match the Gram-stained image to the organism it MOST closely represents.

Bacillus anthracis

The tech working on an aerobic wound culture is identifying a colony that is large, gray, and non-hemolytic on blood agar. The tech prepares a Gram stain of the colony and notices a consistency similar to whisked egg whites. Gram stain reveals a large Gram-positive bacillus. What is the most likely identification of this colony?

Bacillus anthracis

Which of the following organisms display the characteristic "Medusa head" on 5% sheep blood agar (SBA) after 18 hours of incubation at 35°C?

Bacillus anthracis

Which of the following organisms would give the gram stain microscopic results seen in this image?

Bacillus anthracis

The well circumscribed, ulcerating pustule illustrated in the upper photograph evolved over 8 days following direct contact with raw animal hides that had been shipped from Central Asia. The lesion began as a small papule, which progressively enlarged, ultimately ulcerated and became covered centrally with a black eschar. The lower photomicrograph is a gram stain prepared from a colony that grew within 48 hours on blood agar. The most likely agent of this infection is:

Bacillus anthracis ("malignant pustule")

Illustrated in the upper blood agar plate are large, spreading, gray white colonies with a buttery consistency and fimbriated edges. Each colony is surrounded by broad zones of beta hemolysis. The Gram stain in the lower image reveals long, box-car shaped, spore-forming Gram-positive bacilli. Lecithinase is produced on egg yolk agar. These findings are most consistent with a presumptive identification of which of the following?

Bacillus cereus

Which bacterial species is most likely represented by the spreading, gray-white, beta-hemolytic colonies with a "frosted glass" appearance as illustrated in the photograph?

Bacillus cereus

The colonies seen growing on the surface of the blood agar plate shown in the upper photograph were recovered from a blood culture after 36 hours of aerobic incubation at 35° C. A Gram stain prepared from one of the colonies is shown in the lower photomicrograph. The most likely identification is:

Bacillus circulans

The colonies seen in the upper frame, grown after 48 hours of incubation aerobically at 35°C, and the accompanying Gram stain in the lower frame are of an organism uncommonly associated with human disease; however, this organism has been associated with septicemia, bronchopneumonia, osteomyelitis and other infections, particularly in intravenous drug users. What is the most likely identification of the organism?

Bacillus circulans

What is the most likely organism, based on the gram stain photomicrograph?

Bacillus spp.

All of the following Bacillus species wouldhave a wide zone lecithinase reaction, EXCEPT?

Bacillus subtilis

Which of the following is considered a normal skin flora organism?

Bacillus subtilis

Group A beta-hemolytic streptococci are best characterized by which of the following:

Bacitracin sensitivity

A mucoid alpha hemolytic translucent colony suspected of being Streptococcus pneumoniae was isolated from a blood culture. All of the of the following are appropriate tests to make a presumptive or definitive identification of this organism EXCEPT?

Bacitracin susceptibility

Which of the following is a presumptive test for the identification of Lancefield group A Streptococcus:

Bacitracin susceptibility

All of the following are usually associated with Group A Beta Streptococci, EXCEPT?

Bacteremia

Acridine orange is used to detect the presence of which of the following?

Bacteria

What is the MOST common infective agent to be transmitted through blood transfusion that results in morbidity and mortality?

Bacteria

A CSF specimen is received from a patient with suspected meningitis. Positive Gram stain, along with the results shown here suggest what type of condition? Elevated WBC count Neutrophils predominant Marked protein elevation Marked glucose decrease Lactate level = 37 mg/dL

Bacterial meningitis

All of the following organisms are aerobic organisms, EXCEPT?

Bacteroides fragilis

Cultures from a post-abdominal cellulitis specimen grew Gram negative pleomorphic rods with the following characteristics: Grows on KV agar but does not show fluorescenceProduces black colonies BBE agarResistant to penicillin Which of the following is the MOST likely identification?

Bacteroides fragilis

Which one of the following pathogenic anaerobic bacteria is MOST frequently isolated in clinical laboratories?

Bacteroides fragilis

An abdominal wound culture grows E. coli on the aerobic culture. The anaerobic culture has growth of two, gram- negative rods, one of which is aerobic. The other gram negative rod has 2+ growth on BBE plate and is resistant to kanamycin, colistin, and vancomycin disc. What is this organism's identification?

Bacteroides fragilis group

Aspiration material recovered from a ruptured appendix abscess was inoculated to anaerobic culture media per laboratory protocol. Gray colonies (> 1 mm) grew anaerobically in 24 hours on BBE agar, blackening the media. The photograph illustrates the gram stain features of the organism. The bacterial species most likely associated with the abscess is:

Bacteroides fragilis group

The organism that is a strict anaerobe, non-motile, gram-negative bacillus, occurring in abscesses and associated with peritonitis is MOST likely:

Bacteroides spp.

A 43-year-old female presented to her doctor for a routine check-up. Her only complaint was that she had been experiencing watery stools that occasionally contained pus and blood. Examination revealed tenderness in her abdomen. A stool for ova and parasite testing was sent to the laboratory and two suspicious forms were seen. The oblong form on the left measured 53 µm by 60 µm whereas the rounder form measured 45 µm by 37 µm. The parasite is MOST likely:

Balantidium coli

The trophozoite illustrated in the photograph is large, measuring 120 µm, representative of what might be observed in a stool specimen obtained from an immune-compromised patient with low-grade diarrhea. Select from the multiple choice responses to derive a presumptive identification.

Balantidium coli

What is the largest protozoan known to infect humans?

Balantidium coli

Which microscopic, intestinal parasite is the only ciliate that is pathogenic for humans?

Balantidium coli

Referring to the image on the right, the form illustrated is found in stool and measures 45 µm. Please identify the organism:

Balantidium coli cyst

Which of the following protozoa is the largest?

Balantidium coli trophozoite

Which of the following substances, when present in a sample, may mask parasites?

Barium

The bacterial species most likely associated with bacillary angiomatosis is:

Bartonella henselae

The top image shows a 5-day old entire colony with distinct outer borders that was incubated at 30° C. The surface is a delicate silky, light gray-white mycelium. The reverse of the colony appears white. This appearance is non-specific. The bottom image is a photomicrograph of a lacto-phenol blue stained mount of a small inoculum taken from the surface of the colony. What is the most likely identification?

Beauveria

The common name for Taenia saginata is:

Beef tapeworm

The following is the term used to describe the total clearing of the agar surrounding colonies on a blood agar plate as seen in this illustration:

Beta Hemolysis

A patient who was seen in the ED has symptoms consistent with cellulitis. A gram stain from the patient's blood culture revealed gram-positive cocci in pairs and short chains. Blood cultures grew an organism that was susceptible to a 0.04 unit disk of bacitracin. Other characteristics one would expect to see with this bacterial isolate include:

Beta hemolysis, negative catalase, negative CAMP, no growth in 6.5% salt

Although an uncommon isolate in most microbiology laboratories, this bacterial species is included in the microbiota of the mouth and intestinal tract. The colonies on blood agar are irregular in size, smooth, non-hemolytic, entire, convex, and ranging from gray-white to light yellow. Distinctive is the "dog bone" appearance of branching Gram-positive bacilli as illustrated in this photomicrograph of a Gram stain. Biochemical activity is limited to fermentation of glucose and lactose. With these observations, select the presumptive identification

Bifidobacterium species

Streptococcus pneumoniae can BEST be differentiated from the viridans group of streptococci by which characteristic?

Bile solubility

The name of the rapid test seen in the image, often used to differentiate S. pneumoniae from viridans streptococci, in which a drop of 10% deoxycholate was placed on an area of growth, is:

Bile solubility test

A tech working in the laboratory receives a VRE screening culture. Which of the following agars should the tech use to set up the VRE screening culture?

Bile-esculin-azide (BEA) agar with vancomycin

This parasite found in a patient's urine and measures 135 µm by 50 µm. The parasite shown is the causative agent of which disease?

Bilharziasis

This suspicious form, recovered in stool, measures 165 µm by 65 µm. It is responsible for causing:

Bilharziasis

Illustrated in the photograph to the right is a lactophenol cotton blue preparation from a culture of a dematiaceous fungi. This fungi is known to cause phaeohyphomycosis and can be found in sites such as subcutaneous tissue, brain, eyes, and bones. Which of the following fungi is represented?

Bipolaris species

Illustrated in the top photomicrograph is a 4 day old colony growing on Sabouraud's dextrose agar with a smooth dark gray to black surface surrounded by dark gray and white peripheral bands. The colony morphology is not distinctive. The identification is made by observing the septate hyphae and conidia as microscopically observed in the lactophenol cotton blue stained mount obtained from the surface of the colony as illustrated in the bottom photomicrograph. From these observations, select the most probable fungi.

Bipolaris species

The production of polar germ tubes is a characteristic that is associated with which of these dematiaceous fungi?

Bipolaris species

Which culture medium is specifically formulated to recover Salmonella typhi from stool specimens?

Bismuth sulfite agar

The following is the vector for the transmission of Onchocerca volvulus:

Black Flies

The suspicious form pictured here in a red cell (lacking Schüffner dots) is responsible for which of the following conditions?

Black water fever

This bacterial species shows good growth in 48 hours of entire, white, smooth, non-hemolytic colonies on blood agar (image to the left in the composite), and lightly pink pigmented, smooth entire colonies on chocolate agar (image to the right in the composite). This species is included in the class of motile, oxidase-positive non-fermenters, indigenous in the respiratory tract of domestic animals, but can cause human sinusitis and pneumonia in animal caretakers. Carbohydrate utilization is asaccharolytic except for oxidative utilization of maltose, as illustrated in the lower composite image -- a key reaction is rapid urease production, and nitrates are reduced as also illustrated in the lower composite photograph. Based on these observations, select from the multiple choices the identification of this isolate.

Bordetella bronchiseptica

Protozoal parasites that typically do not produce disease in humans are referred to as being:

Commensal

A stool sample was obtained from a patient who had persistent, intermittent diarrhea. A 6 µm cyst was observed using a trichrome stain. Take note of the green-staining central body and small masses of nuclear material that are scattered beneath the outer membrane. What is the most likely identification of this cyst?

Blastocystis hominis

The avoidance of laboratory diagnosis techniques that utilize water is recommended for the identification of which of these parasites?

Blastocystis hominis

The image shows an organism that measures 12 µm and is found in stool. What is the identification of this organism?

Blastocystis hominis

From the following molds, which one is considered an obligate pathogen, causing infections in persons who were previously healthy?

Blastomyces dermatitidis

From the list of fungal species below, select the one for which optimum recovery in a laboratory culture requires the use of an enriched agar base such as inhibitory mold agar, SABHI (Sabouraud's dextrose agar + heart infusion agar), or brain-heart infusion with cycloheximide and chloramphenicol.

Blastomyces dermatitidis

Identify the species of dimorphic fungi in its yeast form as observed under the microscope in this image.

Blastomyces dermatitidis

Illustrated in the top image is a 10-day-old colony growing on the surface of Sabouraud Dextrose with Brain Infusion (SABHI) agar, incubated at 30° C, recovered from an induced sputum sample obtained from a 42-year-old Mid-western farmer. The colonies are not genus/species specific, and appear as a mold with a delicate, silky, cob-web like yellow-white mycelium. The species identification is made by observing the Lactophenol blue-stained tease mount preparation illustrated in the bottom image. With these observations, select the presumptive identification of this isolate from the choices shown below.

Blastomyces dermatitidis

This image illustrates a lactophenol blue mount prepared from a mold recovered after 7 days incubation on brain heart infusion broth. The individual microconidia, each borne by a delicate conidiophore, suggests the mold form of the following organism:

Blastomyces dermatitidis

Which of the following dimorphic molds produces spherical or oval conidia, each supported by an individual conidiophore ("lollipop") as represented in the image on the right?

Blastomyces dermatitidis

Yeast colonies, as illustrated in the top image, can be cultured in the mycology laboratory either by transferring samples from growing colonies to enriched agar incubated at 35o - 37o C, or by setting up a second culture for incubation at the elevated temperature. The yeast colonies appear smooth and pasty, off-white pigmentation. The species identification is made by observing the morphology of a yeast cell as observed in lactophenol blue-stained mounts as shown in the bottom image. With these observations, select the correct presumptive identification of this isolate from the choices listed below.

Blastomyces dermatitidis

The preliminary identification of bacterial species often is made based on the odor produced by colonies recovered on primary isolation media. Which of the following odors would be expected for Eikenella corrodens?

Bleach

The tech in microbiology receives a call from the ER where the doctor suspects a patient has GI anthrax. What should the tech indicate is a proper specimen for collection to detect GI anthrax?

Blood

The tech in microbiology receives a call from the ER where the doctor suspects a patient has inhalation anthrax. What should the tech indicate is a proper specimen for collection to detect inhalation anthrax?

Blood

The image to the right represents parasites from which of the following groups?

Blood Nematodes

Since Brucella species are facultative intracellular organisms that infect the reticuloendothelial system, specimens of choice for recovery include:

Blood and bone marrow

Which of these methods are used to identify prior exposure to Mycobacterium tuberculosis?

Blood tests known as interferon-gamma release assays.

The parasite Endolimax nana trophozoite shows what type of nuclear appearance?

Blot-like karyosome, no peripheral chromatin

Osteomyelitis can only be diagnosed by collection and subsequent culture of a sample collected from which source?

Bone

Each of the following bacterial species are commonly associated with wound infections following a dog bite except?

Bordetella bronchiseptica

Which of the following errors could most likely occur in the preanalytical phase?

Incorrectly collected sample

A 33-year-old livestock farmer, native to central Illinois, gave a one month history of diurnal fever, peaking in the evening and during the night, but subsiding during the daytime. He also complained of muscle aches and easy fatigability. After several negative blood cultures, an organism was finally recovered after 9 days incubation. The colonies shown in the upper photograph appeared on chocolate agar after 48 hours incubation in CO2. Growth was poor on blood agar. The Gram stain prepared from one of the colonies is shown in the lower photomicrograph. The most likely identification is:

Brucella abortis

Which Brucella species has positive H2S production and may or may not need CO2 for growth?

Brucella abortus

All of the following media types should be inoculated for cerebrospinal fluid (CSF), EXCEPT:

Brucella agar plate (BRU)

A tiny Gram negative coccobacilli was isolated on chocolate agar from a wound on a man who had been hunting wild boar. The microbiologist performed the following test:OxidasePositiveUreasePositiveMotilityNonmotileColony morphologySmall, nonhemolytic Which of the following species is most probable?

Brucella species

The small, slowly growing gray-white colonies seen on the blood agar plate were recovered from a blood culture of a 40-year-old farm worker who developed fever and chills leading to septicemia, following ingestion of contaminated milk. The Gram stain of this organism is seen in the lower image revealing small gram-negative coccobacilli in loose clusters. Key to the identification of this blood culture isolate is the rapid urease reaction. From these observations, select from the choices the presumptive identification of this isolate.

Brucella species

This species is the most commonly reported laboratory-acquired bacterial infection and must be handled in a class II or higher biological safety cabinet. They are small gram negative coccobacilli that are strict aerobes and will grow on Sheep Blood Agar and Chocolate agar. They are nonmotile, catalase, urease, and nitrate positive and most strains are oxidase positive. From the choices below, please select the organism matching the microscopic and biochemical reactions listed:

Brucella species

A patient was admitted to the hospital for fever, chills, weight loss, headaches, and fatigue. The patient mentioned that he had cut his hand while hunting wild boar a couple of weeks ago. Blood cultures were received in the microbiology laboratory and several days later a bone marrow specimen on the patient was received. The blood culture was positive after 5 days and the bone marrow grew a small, convex, smooth colony after 48 hours on sheep blood and chocolate agar. A gram stain was performed and demonstrated small Gram negative coccobacilli organisms. Which of the following organisms is the cause of infection for this patient?

Brucella suis

Illustrated in the photomicrograph is the tail portion of an adult worm of a filarial nematode in a peripheral blood smear. These worms measure up to 300 µm in length and commonly inhabit the lymphatics of the inguinal region resulting in swelling below the knee in what is known as "elephantiasis". What is this species pictured, which can be presumptively determined by the orientation of nuclei within the tail section (arrows)?

Brugia malayi

This parasite is found in blood, is sheathed, and measures 200 µm. From the parasites listed, what is the correct identification?

Brugia malayi microfilaria

The stage of viral replication where the envelope is being acquired and the HIV is leaving the host cell is known as:

Budding

A patient with cystic fibrosis is admitted with a fulminant lung infection. A sputum culture grows a non-lactose fermenting, oxidase positive, Gram-negative bacilli. It is pyocyanin negative, nitrate reduction variable, and it is arginine dihydrolase negative.

Burkholderia cepacia

Bacteria may be the agents of infections in plants as well as in animals. This organism is the agent of onion bulb rot in plants, but is also an important agent of hospital-acquired infections in humans.

Burkholderia cepacia

Of the Gram-negative bacilli listed below, which is motile with polar tufts of flagella and can produce yellow pigment?

Burkholderia cepacia

_______________ is predominantly associated with skin and soft tissue infections (SSTIs), such as abscesses, cellulitis, folliculitis and impetigo.

Community-acquired MRSA

The following is a non-fermenting, oxidase positive, motile, opportunistic pathogen that most commonly causes respiratory infections associated with chronic granulomatous disease and cystic fibrosis. On sheep blood agar, the organism is described as being small, entire, gray-yellow colonies. On MacConkey, it may appear light pink as shown in the photograph. Identification tests that assist in the identification include Alk/Non-reactive on TSI, lysine decarboxylase positive, oxidation of glucose, lactose, and xylose. It also does not produce gas from nitrate reduction. Which of the following organisms matches the description?

Burkholderia cepacia

Which bacterial species is most likely represented by the spreading, wrinkled, non-hemolytic colony appearance as illustrated in the photograph?

Burkholderia pseudomallei

Which of the following conditions is associated with the Epstein-Barr Virus?

Burkitt's lymphoma

When treating serious enterococci infections, both a cell wall-active agent, such as ampicillin or vancomycin, and an aminoglycoside, such as gentamicin should be used. Therefore, it is important that this information be reported to physicians by which of the following?

By providing an explanatory note stating the recommended use of combination therapy

Which of the following images shows a Gram stain that is consistent with Nocardia species?

C

Which of the following is the rigid, nonmotile diagnostic stage of the amebae which is generally found in the formed stool?

Cyst

The historical medium of choice for isolation of Francisella is:

Cysteine blood glucose agar

The following statement is true regarding hospital-associated methicillin-resistant Staphylococcus aureus (HA-MRSA) and community-associated MRSA (CA-MRSA)?

CA strains tend to be associated with the PVL gene and skin and soft tissue infections.

Spinal fluid cultures on a 3-day-old infant revealed beta-hemolytic, gram-positive cocci occurring in pairs and chains. The organism was catalase-negative and bile esculin-negative. Resistance to bacitracin was noted. The other test necessary to identify this organism is a positive test by:

CAMP

Any media that supports the growth of Enterococcus species can be used to recover Vancomycin-Resistant Enterococci. However, to improve the recovery of VRE, selective media for VRE will provide the best sensitivity. Which of the following media is most helpful in recovering VRE from surveillance cultures?

CHROM VRE agar

Any media that supports the growth of Staphylococcus aureus can be used to recover Methicillin-Resistant Staphylococcus aureus (MRSA). However, to improve the recovery of MRSA, selective media for MRSA will provide the best sensitivity. Which of the following media is most helpful in recovering MRSA from surveillance cultures?

CHROMagar MRSA agar

What is the one principle that is conserved between all continuous monitoring blood culture systems?

CO2 detection

A tech working on a fungal culture encounters growth of a yeast on the agar plates (hyphae absent). Upon investigation, the tech thinks the yeast may be Cryptococcus species, but is unsure if the organism is Cryptococcus neoformans. What testing can be performed to assist with the differentiation of Cryptococcus species?

Caffeic Acid Test

Direct detection methods are available for Bordetella pertussis from nasopharyngeal specimens; however, caution should be used when collecting the specimen because inhibition can occur based on the type of swab that is used. Which of the following swabs have an inhibitory effect on PCR testing for Bordetella pertussis?

Calcium-alginate swabs on wire shaft

All of the following are types of acid-fast stains, EXCEPT:

Calcofluor white

Which stain is a colorless dye that binds to chitin in fungi and fluoresces with ultraviolet light?

Calcofluor white

Which of the following stains is commonly used to stain chitin in fungal cell walls?

Calcoflur-white stain

A swab is submitted for an influenza screen. The swab used is a cotton swab with a wooden shaft that was placed in a moist transport container. What is the most appropriate next step in this scenario?

Call the RN or physician to let them know that the specimen is unacceptable, and it should be recollected.

A small, microaerophilic, curved, gram-negative rod which was isolated from a diarrhea stool specimen gave the following results: Grew best at 42 ºCOxidase positiveResistant to cephalosporinSusceptible to nalidixic acidHippurate hydrolysis positive What is the MOST probable identification of this organism?

Campylobacter jejuni

A stool culture showing increased number of fecal leukocytes would correlate with an infection of which of the following species?

Campylobacter jejuni

An organism grew at 37° C and 42° C from a stool culture that was oxidase, catalase, and hippurate positive. This organism will be identified as:

Campylobacter jejuni

The recovery of this bacterial species from diarrhea stool specimens requires the use of selective culture media such as Butzler selective media or Skirrow blood agar incubated at 42° C in an atmosphere of 5% oxygen, 10% CO2, and 85% nitrogen. Growth on Skirrow blood agar as illustrated in the upper image are confluent smooth non-hemolytic colonies growing along the streak line with lateral extensions (arrows). Slender, long branching, S-shaped Gram negative rods are observed on Gram stain, as observed in the lower image. Positive reactions for oxidase, indoxyl, and hippurate provide for a more definitive identification. With these observations, select the name of this isolate.

Campylobacter jejuni

Molecular methods are commonly used for direct detection of organisms in clinical specimens. One specimen type that can be used is cerebrospinal fluid. This is important as patients who are immunocompromised can succumb to neural infections quite easily when compared to immunocompetent patients. Which of the following is an advantage of performing molecular testing on CSF patients?

Can detect viable and nonviable organisms

The following statements regarding automated identification systems are correct EXCEPT:

Can reliably identify Francisella tularensis

A potentially pathogenic yeast that is usually found as normal flora in the oropharyngeal cavity and may produce thrush is called:

Candida albicans

Illustrated in the top photograph are small, smooth, 48-hour old white yeast colonies growing on potato dextrose agar. The rudimentary spikes from the surface of the colonies (arrows) indicate that a germ tube test should be performed. The bottom image is the germ tube test for this isolate. What is the identification of this yeast isolate?

Candida albicans

The formation of germ tubes after 2 hours of incubation in plasma at 35° C leads to the presumptive identification of which of the following yeasts?

Candida albicans

This photomicrograph was prepared from tease mounts of 3 day-old smooth, white yeast colonies obtained from an aspirate of nasal fluid of a middle aged patient with sinusitis. Note the clusters of small blastoconidia along the pseudohyphae and also the larger spherical chlamydospores (arrow), as observed in the right lower corner. From the multiple choices below, select the identification of this yeast isolate.

Candida albicans

Which of the following organisms causes thrush?

Candida albicans

The top image is characteristic of the clinical presentation of oropharyngeal thrush that may be observed in patients with AIDS. Specimen samples sent to the mycology laboratory for culture often grow yeast colonies on agar plates within 2 - 3 days of incubation at 30° C. Observed in the bottom photograph is the surface of a niger seed agar plate growing two different yeast species. The one to the left represents the clinical isolate and the one to the right is a control strain. It is important to recognize the colonies of the clinical isolate as it may be potentially resistant to commonly used anti-fungal agents. Select the species of yeast involved in this infection.

Candida dubliniensis

All of the following organisms produce pseudohyphae, EXCEPT?

Candida glabrata

The smooth, pasty appearing 72 hour yeast colonies growing on blood agar shown in the upper image are non-specific and further studies must be performed to make the identification. One of these studies is a cornmeal agar preparation is illustrated in the bottom photomicrograph in which tiny, uniform, spherical cells are arranged in tight clusters. This yeast is commonly recovered from urinary tract infections. Select the most likely yeast isolate.

Candida glabrata

This species of Candida accounts for around 20 percent of urinary yeast isolates.

Candida glabrata

The growth of yellow-white yeast colonies with a smooth or hair-like surface within 2 - 3 days on non-selective culture media generally requires further procedures to make a presumptive identification. Microscopic observation of the subculture of colonies growing on cornmeal agar is one such approach, as illustrated in the photomicrograph. Note the "logs in stream" arrangement of elongated blastoconidia. From the multiple choices, select the name of the presumptive yeast identification.

Candida kefyr

This yeast has been found in respiratory secretions, the vagina, urine, gastric washing and the oropharynx but is mainly thought to cause vaginitis and urinary tract infections. Growth on Cornmeal Tween 80 agar demonstrates elongated blastoconidia that lie parallel to pseudohyphae (like logs on a stream).

Candida kefyr (pseudotropicalis)

All of the following Candida species can be commonly recovered in a clinical specimen of blood, EXCEPT?

Candida neoformans

The growth of yellow-white yeast colonies with a smooth or hair-like surface within 2 - 3 days on non-selective culture media generally requires further procedures to make a presumptive identification. Microscopic observation of the subculture of colonies growing on cornmeal agar is one such approach, as illustrated in the photomicrograph. Note the spider-like colonies that appear along the streak line. From the multiple choices, select the name of the presumptive yeast identification.

Candida parapsilosis

The morphology of yeasts inoculated to cornmeal agar can be helpful in making a species identification. The field of view shown in this photomicrograph is most consistent with the identification of:

Candida parapsilosis

An immunosuppressed patient with a CSF shunt is exhibiting symptoms of a shunt infection. When performing a Gram stain, the organism observed in the image to the right is seen. What is the most likely identity of this organism?

Candida sp.

Which organisms' natural habitat is part of the human microbiota?

Candida spp.

A patient grew out a Staphylococcus lugdunensis and after susceptibility testing, the isolate gave results indicating probable resistance to oxacillin. Which of the following is the best method to detect the mec-A gene to determine if the organism has true oxacillin resistance?

Cefoxitin disk diffusion

A technologist subcultures a positive blood culture and notes the following characteristics on the isolated colonies displayed in the image below: Growth of non-hemolytic colonies with a ground-glass appearance, displaying a "Medusa Head", as indicated by the arrows Gram stain reveals a large, gram-positive rod with central and subterminal spores that do NOT swell the cells Catalase positive Non-motile What would be the MOST likely conclusion and action?

Cannot rule out Bacillus anthracis, refer isolate to your Laboratory Response Network (LRN) Reference Laboratory

After a one week visit in the Philippines, a 42-year-old male missionary had noticed a gradual onset of abdominal pain, belching, and intermittent diarrhea during the past month. Upon further examination, dehydration and electrolyte imbalances with low plasma levels of potassium, sodium, and calcium were detected. The 60 µm ovum, as illustrated in the image, was observed in a stool preparation. Select the correct presumptive identification from the answer choices shown below.

Capillaria philippinensis

Which of the following organisms is indole negative?

Capnocytophaga canimorsus

A fusiform-shaped, Gram negative, oxidase negative bacillus that produces colonies with marginal finger-like projections was recovered from the oral cavity of a patient with periodontal disease. The most likely identification is:

Capnocytophaga ochracea

Human dog bite infections may be caused by each of the following bacterial species except:

Capnocytophaga ochracea

Which Gram negative organism can produce "gliding motility" on agar plates and is a primary cause of juvenile periodontitis?

Capnocytophaga ochracea

Observed growing on chocolate agar after 4 days of incubation are non-descript tiny, circular, smooth colonies. Growth on sheep blood agar is typically absent or minimal. In the Gram stain, as illustrated in the upper photomicrograph, thin, long fusiform Gram negative bacilli are observed. This organism was isolated from a skin abscess at the site of a dog bite. The Kligler Iron Agar reaction was A/A indicating carbohydrate assimilation, with distinctive positive test reactions for dextrose, sucrose, and maltose. With these observations, select the identification of this isolate.

Capnocytophaga species

Which of the following is the primary virulence factor in Streptococcus pneumoniae?

Capsular polysaccharide

The following is the primary virulence factor produced by Streptococcus pneumoniae that prevents phagocytosis:

Capsule

Different species of Neisseria can be differentiated from each other by:

Carbohydrate utilization

The isolate is represented by the slow growing small, gray-white, opaque and non-hemolytic colonies on blood agar. Short, gram-negative bacilli are, lying singly but also in the form of characteristic "rosette-like" clusters (arrows) are observed in the lower photomicrograph. As additional biochemical reactions necessary to confirm a presumptive identification, oxidase and indole reactions are positive; catalase, nitrate and urease reactions are negative. Based on these observations, select from the multiple choices the presumptive identification of this isolate.

Cardiobacterium hominis

Beta hemolytic colonies grew from the blood culture bottle after 18 hours incubation (see image). If the gram stain shows gram positive cocci, which of following tests would be helpful with making a preliminary identification?

Catalase

A tech is working with a small Gram-negative coccobacillus that may be Francisella tularensis. Which of the following tests could the tech use to rule out this organism?

Catalase negative

Which of the following test is the most useful in differentiating Listeria monocytogenes from Erysipelothrix rhusiopathiae?

Catalase production

A rapid urine screening test that can be performed to detect the presence of Staphylococcus species is which of the following tests?

Catalase test

Which of the the following bioterrorism agent categories is the easiest to spread, has the ability to cause major harm, panic, and death, and carries the highest level of risk with regard to national security?

Category A

Which of the following is a TRUE statement concerning the Category A agents of bioterrorism?

Category A agents cause high mortality and the potential for major public health impact.

This organism is very similar to Serratia marcescens, except it is DNA'se negative.

Cedecea davisae

A tech receives a call from the floor regarding antimicrobial therapy. The patient culture yielded an aerobic Gram-negative bacillus and the physician would like to use an antibiotic that inhibits cell wall synthesis. Which of the following antibiotics would be the best choice?

Cefazolin

For an isolate of Escherichia coli, Klebsiella, or Proteus species testing positive for ESBL (Extended Spectrum Beta Lactamases), all of the following antibiotics should be reported as resistant except:

Cefoxitin

Methicillin resistant Staphylococcus aureus (MRSA) is a serious health concern in the hospital environment and also in the community for patients who have had no contact with the healthcare setting. In order to control the spread of MRSA and prevent infection with the organism, it is recommended to screen patients for MRSA prior to being admitted to a healthcare setting. Which of the following antimicrobials is best to use when testing for methicillin resistance?

Cefoxitin

A patient grew out Mycobacterium tuberculosis (MTB) from an acid fast bacilli (AFB) sputum culture. The physician called requesting information on alternative choices for the treatment of MTB, since the patient had tested resistant to the primary drugs of choice. Which of the following antitubercular agents would be recommended for treatment?

Ciprofloxacin

A tech receives a call from the floor regarding antimicrobial therapy. The patient culture yielded an aerobic Gram-negative bacillus and the physician would like to use an antibiotic that inhibits DNA synthesis. Which of the following antibiotics would be the best choice?

Ciprofloxacin

This member of the Enterobacteriaceae was isolated from a stool specimen and gave the following biochemical reactions: TSI: K/A, no gas, no H2S Citrate: Positive Lysine decarboxylase: Negative Ornithine decarboxylase: Positive Indole: Negative This organism agglutinated in Group D Shigella antiserum. All of the above biochemical results are consistent with this identification, EXCEPT?

Citrate

Each of the tests below are appropriately matched with a chemical responsible for producing a positive result, EXCEPT:

Citrate - alpha naphthol

Illustrated in the photograph is a citrate tube. Sodium citrate is converted into alkaline products by bacteria that can utilize citrate as the sole source of carbon, giving a blue color from the conversion of the bromothymol blue indicator. Select the species of Enterobacteriaceae that produces this reaction.

Citrobacter freundii

Illustrated in the top image is a slow-growing, 8-day-old colony growing on Sabouraud Dextrose with Brain Heart Infusion (SabHI) agar obtained from a darkened superficial skin infection. Although the colony is not specific for one of the fungal species causing chromomycosis, the black outer border that extends into the reverse of the colony is consistent. The identification is made by observing the distinctive conidiation illustrated in the bottom image. Which of the following organisms is represented by the description and images shown?

Cladophialophora carronii

Which of the following dematiaceous fungi can cause Chromoblastomycosis?

Cladophialophora species

The type of sporulation illustrated in this photomicrograph of a dematiaceous fungus is:

Cladosporium

Illustrated in the image is the fruiting head of one of the fungal agents of chromomycosis. Note the long chains of elliptical conidia each separated by a distinct scar, called a "dysjunctor". Which of the following choices represents the type of sporulation illustrated in this image?

Cladosporium sporulation

At a minimum, the following class of biological safety cabinet (BSC) must be used when manipulating potential bioterrorism agents and if aerosols are likely:

Class II BSC

Eikenella corrodens is associated with which of the following?

Clenched fist infection

A 35-year-old man presented to his doctor with fever, diarrhea, abdominal pain, and epigastric discomfort. Upon questioning the patient, it was learned that he travels extensively on business and loves to try new kinds of raw fish. The patient is most likely suffering from:

Clonorchiasis

A 65-year-old Asian female presented to the emergency room exhibiting severe abdominal pain, fever and diarrhea. Examination revealed an enlarged liver that was tender to the touch. Patient history revealed that the woman worked in a fish processing plant for years prior to moving to the United States. Her diet was heavy in raw fish. Stool and duodenal contents were collected and sent to the laboratory for cultures and parasite examination. The cultures were unremarkable. This suspicious form was seen in both specimen types. It measures 27 µm by 14 µm. What is the most likely cause for this patient's symptoms?

Clonorchiasis

Illustrated in the photomicrograph is a relatively small pear-shaped trematode ovum, averaging 25 - 35 µm, as might be microscopically observed in a stool sample preparation. The shell is smooth and slightly thickened. Distinctive is the shouldered operculum at the cephalic end of the shell and a small knob at the posterior margin (arrows). Developing larvae at varying stages are observed internally. The adult flukes are most commonly found within the liver bile duct system and may cause obstruction and intermittent jaundice. What is the best presumptive identification?

Clonorchis sinensis

A 25-year-old motorcyclist incurred superficial and deep penetrating lacerations of his right shoulder when thrown off his speeding vehicle into the ditch. The shoulder became painful and continued to swell over the next 24 hours. The bacterial species shown in the upper image was recovered after 36 hours under anaerobic incubation and the lower image illustrates the microscopic features. What is the most likely identification?

Clostridium perfringens

Illustrated in the upper photograph is an adult trematode fluke that in human infections is most commonly found in the distant bile ducts of the liver. The fluke is relatively small, averaging 12 - 20 mm. The lower image is a close in view of this fluke to better illustrate its internal structures. Symptoms during infection may be minimal, but liver enlargement and jaundice may be experienced in heavy infections. Human infections are endemic in southern China. What is considered the appropriate identification?

Clonorchis sinensis

The patient was a 55-year-old male immigrant from Korea. His current symptom was severe jaundice. He had had intermittent less severe bouts of jaundice in the past. During surgery, his proximal bile duct appeared to be enlarged with a nodular area of inflammation. A surgical biopsy was done and a parasite was observed in a stained tissue section residing in the lumen. Further examination revealed a collection of ova within the ovary of this fluke as see in this image (arrow). Which of the organisms listed below is most likely?

Clonorchis sinensis

Which of these parasites are hermaphroditic in their adult phase?

Clonorchis sinensis

This form, which measures 30 µm by 15 µm was found in stool. What is the identification?

Clonorchis sinensis egg

The irregular-sized, gray-white colonies, with irregular margins, as shown in the image to the left in the upper composite photograph, were recovered from a stool specimen in a case of antibiotic associated colitis. The colonies are flat, gray-white and spreading with irregular margins. Some patients with this infection develop pseudomembanous colitis that can be life threatening. Growth is enhanced when Cycloserine-cefoxitin-fructose agar (CCFA) is used, as seen in upper right photograph. The observation of elongated, Gram positive bacilli with distinctive subterminal and central spores in Gram stain mounts provides for a presumptive identification. Additional key identifying reactions is the absence of lipase and lecithinase and a chartreuse pigment under fluorescence light. With these observations, select the presumptive identification of this isolate.

Clostridioides difficile

What organism is responsible for a potentially lethal type of food poisoning caused by improperly canned food?

Clostridium botulinum

Which bacterial species listed is a select agent, which is capable of producing an extremely potent, lethal neurotoxin?

Clostridium botulinum

Which of the following Clostridium spp. produces a toxin that is a potential bioweapon?

Clostridium botulinum

A recto-sigmoidoscopy revealed pseudomembranes in a patient with severe diarrhea following prolonged treatment with ampicillin. Which of the following organisms is MOST likely to be isolated?

Clostridium difficile

Which of the following is the bacterial agent associated with antibiotic-associated pseudomembranous colitis?

Clostridium difficile

Which of the following organisms are gram-positive?

Clostridium difficile

From the choices listed below, which organism is classified as an obligate anaerobe?

Clostridium novyi

Which of the following media would you use to isolate Francisella tularensis:

Cysteine-blood agar

A CSF shunt tip specimen was sent to the microbiology laboratory for culture. The shunt specimen was inoculated to sheep blood agar, chocolate agar, and a thioglycollate broth. After 24 hours of CO2 and non CO2 incubation at 37°C, the sheep blood agar, chocolate agar, and the thioglycollate broth had growth. The microbiology tech evaluated the media and observed the following: Growth: Sheep blood grew small, white non-hemolytic colonies. Chocolate grew small, white colonies. Gram Stain: Gram positive cocci in clusters Biochemical: Catalase positive; coagulase negative Which of the following organisms is most likely the cause of the CSF shunt tip infection?

Coagulase negative staphylococci

The most common cause of acute meningitis associated with CSF shunts is:

Coagulase-negative staphylococci

Parasites that belong to the category Sporozoa are also known as:

Coccidia

The following is a systemic, dimorphic genus that characteristically produces barrel-shaped arthroconidia separated by dysjunctor cells:

Coccidiodes immitus

Although care should be taken when working with all fungus cultures in the laboratory, personnel are particularly prone to develop laboratory acquired infections from the inhalation of airborne species of:

Coccidioides immitis

Illustrated in the top photograph is a 6-day old colony with a gray-white cob-web like mycelium growing on brain-heart infusion agar incubated at 30o C. Note the rim of black pigmentation on the upper margin of the colony. An attempt failed to convert the colony to a yeast form by using 35o C incubation. The H & E-stained tissue section of the lung lesion from which the specimen was taken as might be observed by a pathologist, is illustrated in the bottom image. Considering these observations, what is the identity of this isolate?

Coccidioides immitis

The dimorphic molds exist in both mold and yeast forms depending on the temperature of incubation. In the laboratory, when cultures are incubated at 30o C, all of the dimorphic fungi will produce mold colonies, usually within 10 - 14 days. When cultures are incubated at 35o - 37o C, yeast colonies develop usually within 3 - 5 days, with the exception of one of the dimorphic species. From the options shown below, select the genus that does not produce yeast colonies when cultures are incubated at the higher temperature.

Coccidioides immitis

The image in the upper right indicates the mold form of which dimorphic fungus?

Coccidioides immitis

The top image shows a 5-day-old colony grown on blood agar and incubated at 30o C. It has a delicate cobweb-like, gray-white mycelium. Note the dark gray discoloration on the upper margin where hemoglobin pigment has been absorbed. This colony was recovered from the needle biopsy of a lung nodule that developed three months after a 45-year-old businessman returned from a business trip in Southern California. The definitive identification can be made microscopically from the observation of the distinctive hyphae as presented in the lactophenol blue mount shown in the bottom image. From these observations, select the presumptive identification of this isolate from the choices listed below.

Coccidioides immitis

Within three days, at 25ºC, a sputum specimen placed on Sabouraud's dextrose agar with chloramphenicol and cycloheximide produced moist, grayish growth, with a white aerial mycelium. The patient had a history of travel to national parks in California. The questionable organism is MOST likely:

Coccidioides immitis

Which fungi has a growth rate of 2-21 days and the morphological features seen in the tissue form are round spherules 30-60 µm in diameter containing 2-5 µm endospores?

Coccidioides spp.

The growth of the colonies shown in the upper image was obtained on blood agar from a sputum specimen after 8 days of incubation at 30°C. The lower image is a photomicrograph of a lactophenol cotton blue mount made from a portion of the colony. The diagnosis is:

Coccidioidomycosis

Which of the following fungal infections is endemic in the Southwestern United States desert regions?

Coccidioidomycosis

The disease most commonly associated with the novobiocin-resistant staphylococcus illustrated in this photograph is:

Community-acquired urinary tract infection

In hookworm cases where progressive anemia is present, what additional test procedure should be performed to determine infection in stool specimens?

Concentration technique

The tendency for the cells of Mycobacterium tuberculosis to assemble in linear aggregates as seen in this image of an acid-fast stained preparation is caused by production of:

Cording factor

An uncommon laboratory isolate, the colonies on blood agar, as seen in the top upper frame of the composite image were cultured from the throat swab of a 10 year old girl presenting with a red throat and mucosal pseudomembrane. These tiny gray-white, non hemolytic colonies are non-descriptive. Distinctive are the black pigmented colonies as observed on Tinsdale agar (lower image in the top composite photograph). Illustrated in the lower composite photomicrograph (upper image) are slender gram positive bacilli. Bacilli with meta-chromatic granules are observed in a methylene blue stained microscopic mount (lower image). From these observations, select from the multiple choices the presumptive identification of this isolate

Corynebacterium diphtheriae

Cystine-tellurite blood agar is recommended for the isolation of which organism?

Corynebacterium diphtheriae

The black colonies growing on the surface of this cystine-tellurite agar plate, with dark brown halos surrounding the colonies, is one of the characteristics of:

Corynebacterium diphtheriae

The serum medium and methylene blue stain originally described by Loeffler are both helpful in the identification of:

Corynebacterium diphtheriae

This micrograph is most consistent with the cell morphology of:

Corynebacterium diphtheriae

All of the following are common causes of infective endocarditis, EXCEPT?

Corynebacterium jeikeium

Illustrated in the upper photograph are tiny, gray-white, non-hemolytic colonies growing on the surface of blood agar. Recovery is most often from infections in immune-suppressed hospitalized patients. The Gram stain shows Gram-positive bacilli arranged in a "diphtheroid" pattern. Characteristic for making a species identification of this isolate are negative reactions for all enzymes. From these observations, select the presumptive identification of this isolate.

Corynebacterium jeikeium

Which of the following Corynebacterium species is lipophilic?

Corynebacterium jeikeium

Illustrated in this photograph are latex agglutination reactions of an unknown beta hemolytic streptococcus recovered from a blood culture. Each reaction is labeled by the group number tested. Of the choices listed, which source is most likely the primary infection for the suspected organism?

Deep wound cellulitis

A body fluid was sent to the microbiology laboratory for culture and after 48 hours of non-CO2 incubation, a small catalase positive, non-spore forming, diphtheroid shaped Gram positive rod grew on sheep blood agar. This organism was considered to be a possible contaminate, since this organism is part of the normal skin microbiota. Which of the following organisms grew in the body fluid?

Corynebacterium species

Which one of the following organisms is commonly cultured from the nasopharynx of healthy people but is RARELY pathogenic?

Corynebacterium species

From the following organisms, which one is considered to be the LEAST pathogenic to humans?

Corynebacterium ulcerans

Each of the bacterial species listed below are correctly matched with its identifying characteristic, EXCEPT:

Corynebacterium urealyticum - urease negative

The image shows an antimicrobial susceptibility result for a Corynebacterium species on a 5% sheep blood agar plate. The zone around the 10 µg penicillin disk rules out:

Corynebacterium ureolyticum

Which of the following organisms causes Q fever?

Coxiella burnetii

Illustrated in the upper left image in the composite photograph is a brown pigmented scaling lesion of the skin involving the distal forearm and anterior wrist interspersed with focal dark circumscribed nodules. The image to the upper right are small white yeast colonies with smooth surfaces. The lower images illustrate the microscopic appearance of fluid aspirated from one of the cystic lesions illustrating distinctive yeast cells. Based on these results, select the name of the infection as illustrated.

Cryptococcosis

All of the following fungal species produce pseudohyphae on cornmeal agar, EXCEPT:

Cryptococcus laurentii

An encapsulated yeast that fails to produce a germ tube, is urease positive and produces brown pigment on bird seed agar is found in a blood culture bottle from a patient with septicemia. What is the MOST likely identification?

Cryptococcus neoformans

The colonies shown in this photograph were grown on Guizotia abyssinica (bird seed) agar at 30°C for 72 hours. The most likely identification is:

Cryptococcus neoformans

The top image shows the microscopic appearance of yeast cells within a colony growing on cornmeal tween 80 agar. These same cells may also be observed in a tissue section (bottom image) taken from an area of inflammation. The tissue section is stained with Gomori Methanimine Silver and shows a clear area around the cells. Which of the following organisms could be the cause of this inflammation?

Cryptococcus neoformans

A spinal fluid was sent to the laboratory for testing. When the hematology tech performed the cell differential, she noticed encapsulated yeast as seen in the images to the right. Upon further investigation, she determined that the patient was immunocompromised and had a recent history of pneumonia. Which of the following would be the most beneficial test to determine a diagnosis?

Cryptococcus neoformans antigen test

The India ink preparation is used for presumptive identification of which organism?

Cryptococcus neoformans in CSF

The modified acid-fast stain is primarily used to identify:

Cryptosporidium oocysts

A 50-year-old male domestic airline pilot was rushed to the hospital after complaining of tremendous fluid loss due to severe diarrhea. History revealed that the patient was diagnosed with AIDS 6 months ago. The doctor ordered a battery of tests including a stool for parasite examination. Since the sample was properly labeled indicating that the patient was immunocompromised, the laboratory performed both the standard processing procedures and a modified acid-fast (mod AFB) stain. The mod AFB stain revealed this suspicious form seen in the image which measured a mere 4 µm. This patient is most likely infected with:

Cryptosporidium parvum

What system is used in the clinical laboratory to monitor a patient's current clinical values for a test with previous values?

Delta checks

Polymerase chain reaction (PCR) copies DNA through repeated cycles of three basic steps. What is the correct order of these steps?

Denaturation, annealing, extension

The story might be told that a pathologist, when first viewing an H & E - stained section of an endoscopic biopsy of duodenum (upper left image), may seek a consultation. The specimen was obtained from a patient with a mal-absorption syndrome. After observing tiny acid-fast globules along the intestinal epithelial lining cell (arrows, upper right image), one of the laboratory microbiologists was consulted for an answer. Having a presumptive identification in mind (lower left image), the microbiologist prepared an acid-fast stained smear of intestinal fluid (lower right image) and observed tiny 5 µm in diameter oocysts. From the multiple choices listed, select the presumptive identification, select what parasite the microbiologist might have reported.

Cryptosporidium parvum

The photomicrograph is of a histological section of duodenum in which are observed small, 5 µm in diameter spores that adhere to the surface epithelium. Although a presumptive identification can be made by demonstrating acid fast staining of these spores, monoclonal antibody-based DFA assays of stool specimens provide a more sensitive final identification. Select from the multiple choices the probable identification.

Cryptosporidium species

Which statement about bacterial culture for Clostridioides (Clostridium) difficile is TRUE?

Culture on appropriate media provides an effective means of recovering the organism.

Which of the following molds is classified as a zygomycete?

Cunninghamella species

Illustrated in the top image is a circumscribed three day old colony growing on Sabouraud's dextrose agar recovered from nasal washings of a patient with sinusitis. The colony with a dark green-gray, wooly surface mycelium is not exclusive. Gray-black pigment would be observed on the reverse side. Species identification must be made microscopically. Illustrated in the bottom image is the appearance of a tease mount made from the surface of the colony. From these observations, what is the identification of this fungal isolate?

Curvularia species

The curved, multi-celled, dark brown staining macroconidia divided by transverse septa that can be observed in the photomicrograph on the right is characteristic of which of the following species of dematiaceous fungi?

Curvularia species

The illustration demonstrates a dematiaceous mold that is known to cause phaeohyphomycoses and sinusitis. It produces septate hyphae, geniculate conidiophores and multi-celled, curved conidia with a swollen central cell. The most likely identification is:

Curvularia species

The oval or curved multi-celled, dark-staining macroconidia divided by transverse septa seen in this image is characteristic of:

Curvularia species

A tissue sample is received in the laboratory for fungal culture. How should the tech prepare the sample for inoculation onto agar plates?

Cut/Mince tissue into small pieces with sterile scissors

A CSF shunt specimen was sent to the microbiology laboratory for culture. The shunt specimen was inoculated to chocolate agar and a thioglycollate broth. After two days of incubation in CO2 at 37°C, the chocolate agar had no growth and the thioglycollate broth had growth at the bottom of the tube. The microbiology tech then subbed the thioglycollate broth to an anaerobic blood agar plate and incubated the plate in anaerobic conditions at 37C for 48 hours. After the 48 hour incubation, the anaerobic blood agar plate was evaluated: Growth: Small, white colonies were observed Gram Stain: Gram positive, pleomorphic, diphtheroid-like rod Biochemical: Catalase positive; Nitrate Reduction positive, Sensitive to Vancomycin and Kanamycin Which of the following organisms is most likely the cause of the CSF shunt infection?

Cutibacterium (Propionibacterium) acnes

An anaerobe was recovered from a blood culture after 92 hours incubation. A gram stain of the isolate is illustrated in the photomicrograph. The most likely identification is:

Cutibacterium (Propionibacterium) acnes

The colonies illustrated in the photograph on the surface of an anaerobic blood agar plate are relatively small, measuring 1 - 2 mm in diameter, round, smooth with a shiny surface, and are non-hemolytic. The Gram stain photomicrograph reveals small Gram positive bacilli in short chains and loose diphtheroidal-like clusters. The indole reaction was found to be strongly positive. This isolate is part of the normal flora of the skin, nasopharynx, oral cavity, and the gastrointestinal and urinary tracts. It is commonly recovered as a contaminant from blood cultures, but on occasion may be the cause of skin and shunt infections. From these observations, select the presumptive identification of this isolate.

Cutibacterium (Propionibacterium) acnes

Which anaerobic bacteria incidence is increasing in CSF shunt infections?

Cutibacterium (Propionibacterium) acnes

Adult intestinal roundworms are equipped with this structure that serves as a protective outer layer:

Cuticle

The ingredient added to culture media to enhance the recovery of the dimorphic fungi by preventing the overgrowth of more rapidly growing, saprophytic molds is:

Cycloheximide

Which antimicrobial is used to suppress or kill saprophytic molds in media?

Cycloheximide

Which of the following is the best media for recovery and presumptive identification of Clostridioides (formerly Clostridium) difficile in suspected cases of pseudomembraneous colitis?

Cycloserine-cefoxitin fructose agar (CCFA)

A 27-year-old missionary returned from a three week visit to Panama. He presented to the emergency department with severe watery diarrhea, weight loss, abdominal pain, nausea and vomiting, a low grade fever, and fatigue. Fresh stool specimens were collected and submitted for ova and parasite examination. The images show a wet mount preparation of a cyst seen in the stool and a dry slide of the same cyst stained by modified acid-fast. Cysts are spherical and measure 8µm in diameter. What is the most likely identification of this parasite?

Cyclospora cayetanensis

The infective stage for all of the intestinal amebas is the:

Cyst

The infective stage for the majority of all intestinal amebae is the:

Cyst

Illustrated in the upper image is an H & E stained section of a cyst of the brain observed in an autopsy case. Shown is the thin cyst lining from which secondary cysts, called "brood capsules", are derived. Upon maturation, small oval buds develop within the brood capsules and produce protoscolices known as "hydatid sand" as illustrated in the lower image. These are the anlagen of the adult Taenia solium tapeworm. From the multiple choice list, select the clinical disease represented by this developing cyst.

Cysticercosis

The high power photograph was taken from a saline wet preparation of a stool specimen. The patient, a 45-year-old male with AIDS who recently returned from a vacation to Mexico City, was suffering from recurrent diarrhea. Based on the morphology of the oocyst, select from the multiple choices the most probable presumptive identification.

Cystoisospora belli

The organism in the attached drawing measuring 20 µm x 15 µm was found in stool. What is it?

Cystoisospora belli (formerly Isospora belli) oocyst

The Echinococcus granulosus life cycle requires both an intermediate host (sheep) and definitive host (dogs), as humans are an accidental intermediate. While the eggs are ingested by humans and sheep, what structures need to be ingested by the definitive host, dogs, in order to complete the life cycle of Echnicoccus?

Cysts

The addition of iodine to a direct and indirect wet prep is used to detect which of the following protozoan stages?

Cysts

If you receive a transudate fluid for a Gram stain and bacterial culture, what is the ideal specimen preparation method for the Gram stain?

Cytocentrifugation to create an appropriate smear.

Stenotrophomonas maltophilia and Burkholderia cepacia share each of the following characteristics EXCEPT:

Cytochrome oxidase activity

Infections with all of the following viruses could cause malignant disease, except:

Cytomegalovirus (CMV)

The following Clostridium difficile virulence factor is significant in the cause of antibiotic-associated pseudomembranous colitis:

Cytotoxin A or B

A stool from a 2-year-old girl grew clear colonies on MacConkey agar, red colonies on XLD (without black centers), and green colonies on HE (without black centers). It is ornithine positive and indole negative. It should agglutinate in antisera of which serogroup of the somatic O antigen?

D

Which serogroup of Neisseria meningitidis is no longer recognized?

D

Illustrated in this photograph is the surface of a MacConkey agar plate growing colonies of a non-fermentative Gram negative bacillus recovered from a wound specimen. The iridescent light pink colonies suggest Acinetobacter species. Each of the following characteristics are helpful in supporting this identification EXCEPT:

Denitrification of nitrates

What is the BEST method for detection of Chlamydia trachomatis in cases of sexually transmitted disease (STD)?

DNA amplification techniques

Which of the following microscopic techniques is best suited for direct examination of the infectious agent of syphilis?

Dark-field microscopy

What is the purpose of using alcohol in the Gram stain procedure?

Decolorize all Gram negative organisms

What is the purpose of using alcohol-acetone or acetone in the Gram stain procedure?

Decolorizes all Gram negative organisms

The Laboratory Response Network (LRN) consists of all of the following except:

Department of Defense (DOD)

Which of the following statements is correct regarding the glutamate dehydrogenase (GDH) assay for Clostridium difficile?

Detection of the GDH gene and 16srRNA genes for C. difficile without the presence of a toxin gene indicates a carrier or nonpathogenic state.

How does the modified acid-fast stain differ it from the conventional acid-fast stain?

Detergent

In order to speciate a swarming Proteus organism found on an eosin methylene blue (EMB) agar plate, the best approach would be to:

Determine indole production and ornithine decarboxylase

The diagnosis of diphtheria must be confirmed by:

Determining that a culture isolate is a toxin producing strain

Illustrated in the image shown is a small (10 µm) ameboid-like oval trophozoite with a pair of nuclei, each with prominent karyosome that is often fragmented. This trophozoite was observed in a stool specimen of a person with intermittent persistent diarrhea and fatigue. What is the best presumptive identification?

Dientamoeba fragilis

Illustrated in the photomicrograph is a small 8 µm ameboid-like oval trophozoite with a pair of nuclei each with prominent karyosomes. This trophozoite was observed in a stool specimen of a person with intermittent persistent diarrhea, loss of appetite and flatulence. What is the presumptive identification of this organism?

Dientamoeba fragilis

Which of the following groups correctly matches the parasite with its infective stage?

Dientamoeba fragilis : trophozoite

This parasite measures 12 µm and is found in the stool. It may easily be mistaken for fecal debris, and reported incorrectly as a a nonpathogenic fecal contaminant.

Dientamoeba fragilis trophozoite

In order to obtain an appropriate specimen before preparing a smear for acid-fast bacilli staining in a sputum sample, what must be done to the original sample?

Digestion and decontamination

A 54-year-old Finnish male presented at the local clinic with abdominal pain, weight loss, overall weakness and digestive discomfort. Patient history revealed that the man's diet was rich in raw fish. A complete blood count (CBC) was performed and revealed macrocytic anemia. A stool for parasitic examination was ordered. This suspicious form was seen upon initial screening of the sample. It measures 70 µm by 48 µm. This patient is most likely suffering from an infection with:

Diphyllobothrium latum

Illustrated in the upper image is a short segment of a tapeworm strobila showing a series of compact proglottids. The lower image is a high power photographic view of proglottids that are distinctly wider than long, each with an internal small branching uterus in the form of a tiny rosette. Proglottids are not commonly passed through the stool, but may be seen within segments of bowel that may have been surgically removed because of bowel obstruction. Based on these observations, select the presumptive identification of this organism.

Diphyllobothrium latum

Stool is the specimen of choice for the recovery of which of the following parasites?

Diphyllobothrium latum

The attached diagram of an egg indicates key diagnostic structures for a specific parasite. What is the most likely organism?

Diphyllobothrium latum

Which parasitic infection may result from human ingestion of contaminated fish?

Diphyllobothrium latum

The colonies illustrated on the blood and chocolate agar plates represent a slow-growing bacterial species that is endogenous in the oral cavity and upper respiratory tract. It may be recovered from human bite skin infections incurred during fist fights. Note the pitting of the agar surrounding the colonies growing in the chocolate agar plate. The Alk/Alk non fermentative reaction seen in the Kligler Iron Agar tube to the left in the lower photograph indicates the non-fermentation of glucose, also indicated by the lack of carbohydrate assimilation in the individual carbohydrate reaction tubes to the right of the KIA tube. A reduction of nitrate is seen and decarboxylation of ornithine is also positive. Based on these observations, select from the multiple choices listed the correct identification of this bacterial isolate:

Eikenella corrodens

Which of the following organisms "pits" the agar, and smells like bleach?

Eikenella corrodens

All of the following are functions of the Laboratory Response Network (LRN), EXCEPT?

Eliminate bioterrorism

An organism has been isolated from the CSF of a premature newborn. The organism grew in 48 hours on MacConkey and blood agar (see image). Additional reactions include: Alk/Alk (red over red) on Kligler Iron agar, oxidative utilization of carbohydrates and a positive indole reaction. Which of the follwing is the most likely identification?

Elizabethkingia (Flavobacterium) meningosepticum

Motility is a key initial assessment in the presumptive identification of the nonfermentative gram negative bacilli. All of the following organisms are motile EXCEPT?

Elizabethkingia meningoseptica

All of the following statements regarding the HBV vaccine are correct, EXCEPT:

Employers may require a fee to administer the vaccine.

Which phrase describes enrichment media?

Encourages the growth of specific types of organisms.

A 12-year-old female went to her doctor for her yearly back-to-school check-up. She was in good health and was asymptomatic at the time of the examination. Due to the increased incidence of parasites in the area, the doctor ordered a stool for parasite examination as part of the routine physical testing. Multiple suspicious forms, measuring approximately 9 µm each were seen. Which of the following is most likely the identification of these forms?

Endolimax nana

Illustrated in the trichrome-stained mount of a stool specimen, submitted to rule out a parasitic infection, are small 8 - 10 µm amoebic cysts. Note the 4 nuclei each containing a large karyosome with no peripheral chromatin. From this high power microscopic view, select a presumptive identification from the multiple choice selections.

Endolimax nana

Observed in a stool specimen passed from a person with minor intestinal symptoms is an 8 µm in diameter cyst as shown in the photomicrograph. Note the four nuclei and their distinctive blotlike karyosomes. Based on the microscopic appearance of this cyst, select from the list of answer choices the presumptive identification.

Endolimax nana

Which cyst is identified in Section D of the image shown?

Endolimax nana

This suspicious form, found in stool, measures 10 µm. What is the identification?

Endolimax nana trophozoite

The most common eye complication in patients with candidiasis is:

Endophthalmitis

The amoeba that lives in the gumline of the mouth is known as:

Entamoeba gingivalis

All of the following parasites typically survive human stomach juices except:

Entamoeba gingivalis trophozoite

This parasite resides in the mouth where, when present, measures approximately 17 µm.

Entamoeba gingivalis trophozoite

Recovered in a stool sample, this suspicious form measures 7 µm. What is the MOST likely identification?

Entamoeba hartmanni

The 6 µm in diameter cyst illustrated in the trichrome-stained photomicrograph was inadvertently observed a stool specimen that was being examined for reasons not clinically related to parasitic diseases. Further history revealed that the patient for whom the stool examination was being performed had only rare bouts of mild diarrhea. Based on the characteristics in the illustration and the patient information, the most likely identification is:

Entamoeba hartmanni

Which of the following parasites resembles Entamoeba histolytica, but lacks ingested red blood cells in the trophozoite form?

Entamoeba hartmanni

Select the answer that lists, in order of smallest to largest, cysts of protozoa based on size.

Entamoeba hartmanni, Entamoeba histolytica, Entamoeba coli

Illustrated in the image shown is a 20 µm trophozoite of an amoeba as microscopically observed in a trichrome-stained mount of a stool specimen obtained from a patient with recurrent diarrhea. Based on the morphology of the trophozoite, presumptively identify the parasitic trophozoite.

Entamoeba histolytica

The image shows an iodine stained cyst, measuring 20 µm in diameter, most commonly observed in a stool specimen obtained from a patient with persistent or intermittent diarrhea with or without fever. The nucleus is characterized by a centrally located karyosome. Which of the following organism is depicted in the image?

Entamoeba histolytica

This suspicious form, found in a stool sample, measures 15 µm. What is it?

Entamoeba histolytica

This suspicious form, which measures 20 µm, was recovered in sigmoidoscopic material. Name that parasite!

Entamoeba histolytica

What is this suspicious form, found in a stool sample, and measures 15 µm?

Entamoeba histolytica

Which of the following parasites causes both intestinal and extraintestinal amebiasis?

Entamoeba histolytica

Which of the following parasites is known to contain cytoplasmic ingested red blood cells in the trophozoite morphologic form?

Entamoeba histolytica

Which of the following would be considered the definitive host of a parasite?

Entamoeba histolytica

Which organism will cause amebiasis and is considered pathogenic?

Entamoeba histolytica

From the following amoebae cyst, which one will measure 15 µm, have up to four nuclei, a centrally located karyosome, and evenly distributed chromatin?

Entamoeba histolytica cyst

The object shown in the image at the arrow was found in a formed stool and measured 15 mm with 4 nuclei, small compact karyosomes, and fine, uniform peripheral chromatin.

Entamoeba histolytica cyst

Illustrated in the image shown is a 20 µm amoebic trophozoite that was observed in a random stool specimen from a patient who had no symptoms of a parasitic infection. Several molecular based studies have found that in the analysis of stable DNA polymorphisms, several differences in DNA zymodeme patterns were found to encode for genetically different strains of Entamoeba histolytica. As some of these strains were found to be non-pathogenic, it has been recommended that the laboratory report be altered to draw attention to this possibility. Select from the choices below the report that should be issued.

Entamoeba histolytica/dispar

The appropriate media for the isolation of anaerobic bacteria from any source would normally include all of the following except:

MacConkey agar

Shown in this photograph are three tubes of Moeller decarboxylase broths, containing from left to right, the amino acids lysine, arginine, and ornithine respectively. A red-blue reaction indicates decarboxylation of the amino acid; yellow is negative. From the bacterial species listed, these reactions are most likely caused by:

Enterobacter aerogenes

The reactions observed in the photograph to the right reveals a motile, gas producing, lactose fermenter that produces acetyl methyl carbinol in VP broth and has the ability to utilize sodium citrate as its sole source of carbon. The most likely identification is:

Enterobacter aerogenes

A unidentified colony was inoculated to the surface of a filter paper strip impregnated with cytochrome oxidase reagent (dimethyl-p-phenylenediamine dihydrochloride) as shown in the picture on the right. The family of bacteria ruled out by the reaction seen is:

Enterobacteriaceae

A situation may arise when a pathologist recognizes the presence of a parasite in an H & E - stained section within the lumen of the appendix, as seen in the upper Image. Studies of additional fields of view in the slide may locate the ovary and reveal the morphology of the ova contained within, as is observed in the lower image. Based on these observations, select the presumptive identification of this parasite.

Enterobius vermicularis

All of the following nematodes are consistent with the 50 µm ovum illustrated in this image EXCEPT one. Select the genus and species of the nematode whose ovum is NOT consistent with the image.

Enterobius vermicularis

The 30 X 50 µm ovum illustrated in the image are most commonly observed by microscopic examination of transparent adhesive tape mounts of perianal skin of children who have complained of nocturnal anal pruritus. What is the most likely presumptive identification?

Enterobius vermicularis

The upper photograph is of a 10 mm long nematode adult; the lower photograph is a close in view illustrating the transparent wing-like alar anterior expansion (blue arrow). These adult nematodes occupy the intestine and may occasionaly be seen at the anal opening of patients with diarrhea. Select from the answer choices below the presumptive identification of this nematode.

Enterobius vermicularis

What is the only nematode egg that is characteristically flattened on one side?

Enterobius vermicularis

Which of the following parasites has the egg as the infective stage of the parasite for humans?

Enterobius vermicularis

A 6-year-old female presented to the local clinic complaining of intense perianal itching and diarrhea. The doctor ordered a cellophane tape prep and stool for routine culture and parasitic examination. The cellophane tape prep revealed suspicious form on the left. The stool culture was negative. The form on the right was seen upon examination of the stool for parasites, which measures 10 µm. What are the two forms present in the image, from left to right?

Enterobius vermicularis and Dientamoeba fragilis

This suspicious form, seen in a cellophane tape preparation, measures 54 µm by 28 µm.

Enterobius vermicularis egg

Which of the following Enterococcus species is motile, mannitol positive, pyruvate negative, and is a rare cause of clinical infections?

Enterococcus casseliflavus

Illustrated in the photograph is a bile esculin agar plate inoculated with a bacterial isolate from a urinary tract infection. The most likely identification is:

Enterococcus faecalis

The bile esculin test has been used to determine if an organism can hydrolyze esculin. Esculin fluoresces, so if it is not hydrolyzed, the tube will fluoresce (bucket B), but if it is hydrolyzed, no fluorescence is seen (bucket A). Which of the following organisms hydrolyzes esculin?

Enterococcus faecalis

The upper image is a photomicrograph of a Gram stain prepared from a positive blood culture obtained from a 68 year old female with an indwelling urinary bladder catheter. Smooth, gray, faintly beta hemolytic colonies were recovered in subcultures of the positive bottle. The tubes shown in the lower photograph are: an esculin slant (left) displaying intense brown coloration a 6.5% sodium chloride broth (right) showing cloudy growth The most likely identification is:

Enterococcus faecalis

Which of the following is the preferred specimen type to culture a soft tissue infection?

Fluid or exudate expressed directly into a sterile specimen cup.

Illustrated in the top left image of the composite photograph is a well-circumscribed, actively progressing pink scaling lesion on the groin, termed tinea cruris or more commonly "jock itch". Illustrated in the lower left frame is a 3-day old colony growing on SABHI agar with a gray-yellow smooth surface with radiating spicules at the periphery. The microscopic features are presented in the right upper and lower photomicrographs of the slide mounts. Select the identification of this dermatophyte.

Epidermophyton floccosum

Illustrated in the top photograph is a 4-day growth of silky, light gray-white to yellow colonies grown on Sabouraud's dextrose agar incubated at 30° C, recovered from an "athlete's foot" infection (tinea pedis) of a young football player. Note the projection of delicate hyphae to the periphery of the colonies. The identification can be made by observing the conidia formations in the lactophenol blue stained mount prepared from the surface of one of the colonies. With these observations, select the species identification from the multiple choices.

Epidermophyton floccosum

Which of the following viruses requires a complex lymphoblastoid cell culture, and is rarely, if ever, diagnosed by culture?

Epstein-Barr Virus

Which two antibiotics are used to confirm the presence of carbapenemase production in Enterobacteriaceae?

Ertapenem and Meropenem

Which of the following organisms are Gram positive?

Erysipelothrix

Although it is actually non-motile, which Gram-positive, catalase-negative organism produces "bottle brush" growth from the stab inocuation in a gelatin agar tube at 22° C, along with hydrogen sulfide production in TSI agar?

Erysipelothrix rhusiopathiae

Which of the following organisms shows a characteristic "test tube brush-like" pattern at 22 degrees Celsius?

Erysipelothrix rhusiopathiae

The organism pictured below was a Gram positive rod isolated from a sore on the hand of a fish market employee. It is shown on triple sugar iron agar. The organism is also catalase negative and non-spore forming. The most likely identification is:

Erysipelothrix rhuziopathiae

A D-test is performed on gram positive cocci to determine inducible resistance to clindamycin when the isolate is sensitive to clindamycin and resistant to which antibiotic?

Erythromycin

Which one of the following organisms is typically urease negative:

Escherichia

A patient presents to the emergency room with hemorrhagic diarrhea. A stool specimen was sent to the microbiology laboratory for culture. The specimen was plated on blood agar, MacConkey (MAC) agar, and Sorbitol MacConkey (SMAC) agar. A Gram-negative, oxidase negative rod (bacilli) grew as a lactose fermenter on the MacConkey agar and as clear colonies on Sorbitol MacConkey agar. Biochemical testing revealed the organism was lysine decarboxylase positive and did not produce hydrogen sulfide (H2S). Which organism is suspected?

Escherichia Coli possibly 0157:H7

Observed growing on the surface of a blood and MacConkey agar bi-plate shown in the upper photograph are large, smooth, entire colonies after 24 hours incubation. The colonies growing on blood agar are yellowish-white; those on MacConkey agar are pink with precipitation of bile salts extending into the agar, better seen in the lower image. A positive acid/acid reaction with gas on Kligler Iron Agar (not shown) and the detection of indole identify this isolate as:

Escherichia coli

The acid/acid reaction shown in the photograph of a Triple Sugar Iron (TSI) Agar reaction tube indicates the recovery of a bacterial species that ferments both glucose and lactose. Also, is the absence to the formation of any black pigment which indicates one of the Enterobacteriaceae that does not produce hydrogen sulfide (H2S). Select the species producing this acid/acid, H2S negative reaction.

Escherichia coli

The tubes shown in this photograph reading from left to right are Kligler Iron Agar (KIA), tryptophane broth for detecting indole and Simmon's citrate. The KIA tube shows an entirely yellow slant and butt, the indole tube shows a layer of red color, and the Simmon's citrate tube is green in color. Of the bacterial species listed, the one most likely to produce the reactions observed is:

Escherichia coli

Which Enterobacteriaceae is the most common cause of uncomplicated urinary tract infections (UTIs)?

Escherichia coli

Which of the following is a common cause of urinary tract infections?

Escherichia coli

To accurately identify aerobic actinomycetes to the species level, the use of molecular methods, such 16S rRNA, can be used. However, there are limitations in identifying Nocardia and other aerobic actinomycetes by molecular methods. All of the following are limitations, EXCEPT?

Extracting DNA

A 21-year-old male presented in the emergency room with symptoms resembling a liver infection. The patient complained of abdominal pain, fever, cough, nausea, vomiting and constipation alternating with diarrhea. Further examination revealed the presence of a hepatic abscess. The form in the attached image was recovered following parasitic examination of a sample from the abscess and measures 20 µm. What condition is the patient most likely suffering from?

Extraintestinal amebiasis

Which of the following best describes the morphological characteristics of Mucor species of fungi?

Extremely rapid growing (1-3 days), wooly and gray to brown, or gray-black colonies; tissue form shows large, ribbonlike, twisted pieces of aseptate hyphae with occasional septa

To screen for the Methicillin-Resistant Staphylococcus aureus, all of the following collection sites are appropriate EXCEPT?

Eye

When vitreous fluid is collected, it must be transported to the laboratory within 15 minutes and set up immediately for culture. This specimen type must be handled with care as this specimen type is not easy to obtain. What body site is this specimen collected from?

Eye

Serotypes of Salmonella are differentiated by various antigens found within the organism. All of the following antigens are used to serotype Salmonella EXCEPT?

F1 antigen

Which of the following is a confirmatory test for syphilis?

FTA-ABS

One of the key biochemical characteristics by which Escherichia coli serogroup O157 can be screened from stool specimens is?

Failure to ferment sorbitol

A positive RPR test and a negative FTA-ABS test is most likely the result of:

False positive reaction

Which classification is defined as encompassing a group of organisms that may contain multiple genera and consists of organisms with a common attribute?

Family

Illustrated in the close-in high power microscopic view is a large spherical ovum measuring 130 µm as it may appear in a mount of fecal material. These ova often have a brown staining that suggests passage through a biliary duct on its way through the large intestine. Identifying characteristics include a thin, smooth shell and an indistinct, flat, non-shouldered operculum (blue lines). Based on the appearance of this ovum, select from the multiple choices the correct presumptive identification.

Fasciola hepatica

The 20 mm mature adult fluke illustrated in the photograph has a normal habitat in the liver bile ducts. Humans become infected by ingesting raw or undercooked water plants contaminated with infective metacercaria. These adult flukes are only observed during surgery involving the liver or at autopsy. Intermittent upper abdominal discomfort and low grade jaundice may be experienced. From the multiple choices listed, select the presumptive identification of this fluke.

Fasciola hepatica

The common name of which parasite is the sheep liver fluke?

Fasciola hepatica

What is the methodology used for detecting the presence of bacteria in blood samples that are loaded onto a BACTEC analyzer?

Fluorescent change

A 55-year-old female, who recently returned from an extensive trip to China, presented to her physician complaining of diarrhea and abdominal cramps. The doctor ordered a complete blood count (CBC), comprehensive metabolic panel (CMP), and stool for culture and parasite examination (O & P). The CBC revealed pronounced eosinophilia. The CMP and stool culture were unremarkable. The O & P revealed suspicious forms like the one below that each measured approximately 140 µm by 80 µm. This patient is most likely infected with:

Fasciola/Fasciolopsis eggs

This parasite is found worldwide, particularly in areas in which sheep and cattle are raised. The natural host for the completion of this parasite's life cycle is the sheep. Humans often serve as accidental hosts. Which of the following conditions may be associated with the presence of this stool parasite from a human measuring 130-150 µm long by 60-90 µm wide?

Fascioliasis

Illustrated in the photograph is a large trematode fluke averaging 3.0 - 7.0 cm. This fluke resides primarily in the small intestine. Characteristic is the rounded cephalic end, the convoluted uterus in the anterior half of the fluke, and a delicate branching testes in the posterior half. Humans become infected by ingesting metacercaria contaminated water vegetables. Select the presumptive identification.

Fasciolopsis/Fasciola species

This parasite may inhabit the small intestine or take up residence in the bile ducts. Its egg typically measures 145 µm by 75 µm.

Fasciolopsis/Fasciola species egg

In traditional culture or antigen detection methods, the sensitivity of detection is adversely affected by which of the following?

Fastidious growth requirements and delays in transport

All of the following are characteristics of Burkholderia pseudomallei, EXCEPT?

Fat, gram-postive rod

Each of the following characteristics will differentiate between Listeria monocytogenes and Erysipelothrix rhusiopathiae except:

Fermentation of glucose

Parvovirus B19 is the only human pathogen in the family Parvoviridae. It is most known for its association with which of the following diseases?

Fifth disease

Which of the following terms is used to describe the appearance of rod-shaped bacteria?

Filamentous

As one of the morphological families of parasites, a feature that characterizes various Nematode species is:

Filariform larvae may serve as an infective form for humans.

What is the purpose of the iodine that is used in the Gram stain procedure?

Fixes the crystal violet to the cellular components of gram-positive bacteria.

Trichomonas, Giardia, and Chilomastix belong to the following parasitic group based on the type of motility:

Flagellates

Houseflies are a possible transport host for which of these categories of parasites?

Flagellates and amebae

Parasites of humans are classified into six major divisions. Protozoa is one of those divisions. Which of the following belongs to this classification?

Flagellates and ciliates

The image shows a variety of colony elevations. Which colony elevation description matches with figure B in the image?

Flat

How would this Gram stained smear be correctly described?

Gram-negative bacilli

What are the structures indicated by the arrows in this field from a Gram-stained smear?

Gram-positive bacilli

Which of the following best describes the organisms seen in the attached image?

Gram-positive bacilli

One of the colonies from an anaerobic culture demonstrated the Gram stain in the illustration. The best description of this organism that would aid in the identification is:

Gram-positive bacilli with spores

This image is of a Gram stain prepared from a positive blood culture. Which of the following choices is the MOST appropriate report that the tech should provide to the physician?

Gram-positive cocci in chains

A Gram stain of serous exudate is shown in the image. What should the tech report to the physician?

Gram-positive cocci in tetrads and clusters present

Which of the following best describes the organisms seen in this illustration:

Gram-variable

The infectious disease process in which large numbers of activated macrophages and histiocytes are collected at the site of inflammation is called?

Granulomatous

These suspicious forms were recovered in cerebrospinal fluid (CSF). They are responsible for causing:

Granulomatous amebic encephalitis

How long after hospitalization would stool samples be rejected for testing for parasitic infections?

Greater than 72 hours

Which of the following statements represents alpha hemolysis on 5% sheep blood agar?

Green area around bacteria; incomplete hemolysis

Asaccharolytic use of glucose would be indicated by which of the following reactions in OF glucose tubes?

Green in both tubes with a little blue at the top of the open tube

Illustrated in this photograph is a blood agar plate inoculated with a beta hemolytic streptococcus obtained from a throat culture of a patient with acute pharyngitis. A 0.04 µg bacitracin (left) disk and a SXT disk (right) had been placed in the areas of streaking. The reactions observed allow the most likely presumptive identification of a streptococcus belonging to Lancefield group:

Group A

Which one of the following organisms is sensitive to bacitracin:

Group A Streptococcus

A positive CAMP reaction and hippurate hydrolysis are key in identifying which beta-hemolytic streptococci?

Group B

A ß-hemolytic isolate on SBA revealed a Gram-positive cocci arranged in chains. The isolate was catalase negative, PYR negative, bacitracin resistant, and positive for CAMP and hippurate hydrolysis. What is the presumptive identification of this isolate?

Group B streptococci

Which of the following culture media bests supports the growth/identification of Salmonella species?

Hektoen enteric agar

A culture was performed on a stool sample. After growth was obtained on the blood agar plate, the gram stain showed curved gram negative rods. The oxidase, catalase, and urease were positive. What is the most likely bacterial identification?

Helicobacter pylori

Illustrated in this photograph is an H & E-stained section of a gastric biopsy obtained from a patient with suspected peptic ulcer disease. Based on the biopsy findings, the bacterial species that would most likely be recovered is:

Helicobacter pylori

The bacterial species presented here serves as the causative agent of active chronic gastritis of the lower pyloric antrum of the stomach with the complications of peptic ulcer disease and less commonly carcinoma. Small, curved, plump bacilli are seen on stains of tissue sections obtained from infected intestinal mucosa as illustrated in these photomicrographs. This ulcer and carcinoma producing bacterium can be presumptively identified by the use of the urea breath test in which strong urease produced by this bacterial species is detected by capturing radioactive labeled CO2 in the exhaled breath from an infected patient. From these observations, select the causative bacterial species.

Helicobacter pylori

The organism seen in the image is found in the stomach mucosa and presumptive identification is often obtained from a positive urease test. Select the organism below.

Helicobacter pylori

Which of the following species of bacteria is positive for rapid urease production, as demonstrated by a color change in urea agar from yellow to pink within two hours?

Helicobacter pylori

What is the primary target of HIV?

Helper T-cell lymphocytes

What two glycoproteins are expressed on the surface of influenza A viruses and are used for subtyping of the viruses?

Hemagglutinin and Neuraminidase

Chocolate agar is recommended for the detection of Haemophilus species as it contains the following:

Hemin and NAD

All of the following organisms have been linked to cause endocarditis EXCEPT?

Hemophilus influenzae

Which of the following Hepatitis viruses is (are) transmitted through the fecal oral route and may be implicated in infections transmitted through contaminated food and water?

Hepatitis A

Which of the following is a DNA virus?

Hepatitis B virus

A single adult worm that contains both male and female sex organs is known as:

Hermaphroditic

The adult worms of which of the following parasites resides in the human intestine?

Heterophyes heterophyes

The mechanism by which certain strains of Enterococcus species have developed resistance to the synergistic combination of an aminoglycoside and beta-lactam antibiotics is considered:

High level gentamicin resistance

Illustrated in the top image is the surface of a blood agar culture plate incubated at 35°C for 3 days. Note the growth of tiny smooth, pasty, yellow-white yeast colonies. Although a presumptive identification might be made from the macroscopic morphology, confirmation is made by observing the yeasts forms in the lactophenol stained mount observed in a tease mount prepared from one of the colonies. From these observations, what is the most likely identification?

Histoplasma capsulatum

In the late 1990's, an outbreak of pneumonia was experienced by several high school students involved in a clean-up day held in a Midwestern community. One student experienced a severe disseminated infection. The colony growing on Sabouraud Dextrose with Brain Heart Infusion (SABHI) agar and incubated at 30o C and shown on the top photograph was recovered from an induced sputum specimen. The colony matured in 8 days, presenting a hair-like, cottony surface mycelium. The identification was confirmed by observation of the lactophenol tease mount obtained from the surface of the mycelium. From the list of choices below, select the name of this isolate.

Histoplasma capsulatum

Large, one-celled, smooth-to-tuberculate macroconidia, and smooth or echinulate microconidia are typical of mycelial phase growth of which organism?

Histoplasma capsulatum

Of the dimorphic fungal species listed below, which has the longest time of recovery in primary culture?

Histoplasma capsulatum

The colonies shown in the upper image were obtained on blood agar from a sputum specimen after 10 days incubation at 30°C. The lower image is a photomicrograph of a lactophenol blue mount made from a portion of the colony. The delicate cob-web appearance of the colonies on blood agar (upper image) and the production of macroconidia with a conspicuous prickly surface as seen in the lower image are characteristic of:

Histoplasma capsulatum

The presumptive diagnosis of fungal infections may be assisted based on the geographic location or sites in which they have become endemic. One such condition, is colloquially referred to as "Spelunker's Scourge". This condition occurs after a tour or work in underground caves located in the Midwest, where dust contaminated with bird and bat dung is inhaled. Select the name of the fungus from the choices shown below that causes this endemically-acquired respiratory infection.

Histoplasma capsulatum

The transmission of which of the following organisms is associated with the guano of bats?

Histoplasma capsulatum

Which one of the following organisms can be isolated from bone marrow specimens?

Histoplasma capsulatum

The colonies shown in the upper image were obtained on blood agar from a sputum specimen after 10 days of incubation at 30°C. The lower image is a photomicrograph of a lactophenol blue mount made from a portion of the colony. The diagnosis is most likely:

Histoplasmosis

The morphologic structure of select tapeworms that is most likely responsible for piercing the human intestinal wall is/are called:

Hooklets

Which of the following would be considered the definitive host of a parasite?

Host in which parasites reproduce sexually

What is the medium of choice for isolating Gardnerella vaginalis?

Human blood bilayer Tween (HBT) agar

An occupation or avocation that should be avoided to prevent infection with Francisella tularensis is:

Hunting and skinning small game

Mycobacterium tuberculosis can be identified from body fluids in disseminated infections through molecular testing. In fact, antibiotic resistance can be detected in this organism as well by using isothermal amplification. However, this organism must be grown in culture before testing can be performed. All of the following are examples of isothermal amplification methods EXCEPT?

Hybridzation

The selective medium XLD is seen in this illustration. What is the significance of the black colonies observable on this plate?

Hydrogen sulfide production

A 7-year-old male presented to the local clinic experiencing mild, yet annoying, abdominal pain, diarrhea and nausea. Patient history revealed that the child lives in a shack where sanitation practices are marginal, at best. The dwelling is infested with rats and multiple insects. Stool was collected and submitted for an ova and parasites examination. Numerous suspicious forms, as depicted in the image to the right, measuring 60 µm by 75 µm were seen. This child is MOST likely infected with:

Hymenolepis diminuta

Illustrated in the photograph is a close in view of a 70 µm oval ovum with a thin, smooth outer shell and an inner membrane containing three pairs of hooklets (hexacanth embryo). This ovum is indigenous primarily in rats and mice and only rarely found in human feces. When found, the infected person usually has minimal symptoms; however, in heavy infections, particularly in those who are immune-suppressed, abdominal pain, diarrhea and anal pruritis may be experienced. What is the best presumptive identification of this tapeworm ovum?

Hymenolepis diminuta

The 70 µm ovum illustrated in the high power microscopic view of a saline preparation is uncommonly found in human feces. The cestode represented by this ovum is more commonly found in rats and mice, but infections may be uncommonly transmitted to humans. Water or food contaminated with arthropod related insects within which the cysticercoid larval forms develop may be inadvertently ingested. Once in the human intestine, these larvae develop into adults that attach to the lining cells, and excrete ova that may be observed in fecal specimens. From the multiple choices listed below, select the name of the cestode represented by this ovum.

Hymenolepis diminuta

This suspicious form, found in stool, measures 54 µm by 32 µm. What is the identification?

Hymenolepis egg

In the upper photograph is a short, thin, thread-like adult worm. In the lower photograph is show the scolex of this worm, with a protruding armed scolex and a row of hooklets. Also known as the "dwarf tapeworm", what is this cestode that commonly infects children?

Hymenolepis nana

Select the genus/species for the ovum (30-47 µ m) observed on high power in the unstained wet mount image.

Hymenolepis nana

This image is of a 45 µm ovum that may be observed in stool specimen preparations. In patients with HIV immune-suppression, many ova may be seen in stool specimens in cases of heavy infection. Abdominal pain, bloating, diarrhea, and possible bowel obstruction may be presenting symptoms. Select the presumptive identification of this tapeworm ovum from the multiple choice answers listed below.

Hymenolepis nana

What organism egg is depicted by the drawing on the right? This egg is found in stool and measures 45 µm by 25 µm.

Hymenolepis nana egg

A stool specimen can be suspected of harboring Vibrio cholerae if it possess which of the following characteristics?

If the stool is watery with a high pH and flecks of mucus.

All of the following statements about blood cultures are correct EXCEPT?

If two separate sets (two bottles each set) of blood cultures are requested, draw them both from the same site at the same time.

Enteroviruses are common etiologic agents of percarditis and myocarditis. To identify a viral infection, viral cultures or immunoassays are typically the tests of choice. However, viral nucleic acid probe testing may be most appropriate in which of the following situations?

If viral culture is too slow to grow or not possible

The cestodes or tapeworms can be identified by the unique appearance of their eggs. Examine the image at the right and consider the following choices. Each is a correct match of the egg with its species, EXCEPT:

Image A = Echinococcus granulosus

Review each matched pair. Each correctly matches the bacterial species with its Gram staining reaction and morphology EXCEPT:

Image B = Moraxella catarrhalis

Refer to the images at the right. Image A is delta amino levulinic acid viewed with ultraviolet light Image B is buffered charcoal yeast extract agar viewed with ultraviolet light Image C is MacConkey agar Image D is DNAse agar. Review each of the following names of the bacterial species with the appearance and reactions of the colonies seen on the media listed. Each is a correct match of the species with its appearance on the media EXCEPT:

Image C = Klebsiella pneumoniae

Pictured here is an Echinococcus granulosus hydatid cyst. Identify the object(s) that B is pointing to.

Immature scolices

Illustrated in this image is a field of view microscopically observed on a Scotch-tape preparation. Based on the morphology and presentation of these ova, an identification of Enterobius vermicularis can be made. The optimum time to obtain Scotch-tape samples of peri-anal skin to recover these ova is:

Immediately after waking up

When following sentinel laboratory procedures and protocols, any isolate that cannot be ruled out as one of the "select agents" that might be used in acts of bioterrorism should be:

Immediately referred to the nearest LRN reference laboratory

Which one of the following statements is true regarding the 2009 H1N1 virus?

In 2009, the novel H1N1 virus spread during warmer months.

Blood culture bottles used in continuous monitoring systems, such as the BacTec, uses resins or charcoal to do which of the following?

Inactivates and absorbs out antimicrobial agents

The purpose of the additive SPS (sodium polyanethol sulfonate) that is in continuous monitoring system blood culture bottles, is all of the following EXCEPT?

Inactivates and absorbs out antimicrobial agents

The cyst as illustrated in the photograph was observed in a permanently stained smear of a stool specimen. Making a presumptive identification would be difficult because of the poor quality of the stain and the lack of internal detail. From the multiple-choice answers listed below, select the most likely cause for the poor staining quality observed in this cyst.

Inadequate stool fixation

A male urethral specimen was sent to the laboratory for a gonococcal culture and Gram stain. The specimen was received on a calcium alginate swab and cultured to chocolate and Thayer-Martin agars. A Gram stain was performed and presented intracellular and extracellular Gram negative diplococci. After 24, 48, and 72 hours of 37°C incubation in CO2, no growth was seen on either chocolate or Thayer-Martin agars. Which of the following is the most probable cause for lack of Neisseria gonorrhoeae growth?

Inappropriate swab was used for collection

Which of the following is correct regarding C-reactive protein (CRP)?

Is usually elevated in pediatric bacterial infections

A patient grew out Mycobacterium tuberculosis (MTB) from an acid fast bacilli (AFB) sputum culture. The physician called requesting information on drugs of choice for the treatment of MTB. Which of the following antitubercular agents would be recommended for treatment?

Isoniazid

In multi-drug resistant tuberculosis (MDR-TB), which drugs normally used in first-line treatment of TB are ineffective?

Isoniazid and rifampin

A patient grew out Mycobacterium tuberculosis (MTB) from an acid fast bacilli (AFB) sputum culture. The physician called requesting information on which four primary drugs should be used for the treatment of MTB. Which of the following primary antitubercular agents would be recommended for treatment?

Isoniazid, Rifampin, Ethambutol, and Pyrazinamide

Bob is a MLT at the local VA hospital. Tonight he is assigned to perform set-up and read Gram stains on newly received specimens in the Microbiology department. He ported reported a superficial wound Gram stain as having Gram negative rods, when he realized he must have over decolorized the slide and the rods reported are actually Gram positive. What should Bod do next?

Issue a corrected report

A tech is working on a wound culture and identifies Staphylococcus aureus in the culture. When inputting the data into the patient report in the LIS, the tech accidentally enters Staphylococcus epidermidis instead. How should the tech handle correcting this report?

Issue a corrected report which incidates both the initial incorrect report and the correct report

A tech is working on wound cultures and comes across a culture that has no growth on the agar plates after 24 hours of incubation. How should the tech report this culture?

Issue a preliminary report of "No growth in 24 hours"

A tech is working on a blood culture and after 24 hours of growth, there are small gray, non-hemolytic colonies, resembling Enterococcus species. Gram stain of the colonies indicate Gram positive cocci in pairs and chains. The tech must set up a panel for full identification and sensitivity, which will not be ready until tomorrow. How should the tech report the culture today?

Issue a preliminary report of Gram-positive cocci

What is the purpose of calcofluor white in the direct examination of patient specimens for fungal elements?

It binds to the polysaccharides in the chitin of the fungus.

Which one of the following statements about Campylobacter jejuni is false?

It does not require special incubation conditions to grow in culture.

Which one of the following statements about E.coli O157:H7 is false?

It ferments sorbitol rapidly

All of the following statements concerning Clostridium difficile are true, EXCEPT?

It is an aerobic organism.

All of the following statements about Coxiella burnetii are true, EXCEPT:

It is best diagnosed by culture of the organism

This organism, identified as a Klebsiella oxytoca, was recovered from the blood of an elderly patient with an infected anal fissure . The Vitek identified this organism as an ESBL. After reviewing the Kirby-Bauer plate and susceptibility interpretations, what is the resistance mechanism demonstrated by this organism?

K-1 beta-lactamase

In order to identify an isolate as Yersinia enterocolitica, it must be lysine-negative and demonstrate which of the following?

K/A on Kligler's iron agar

Norcardia species can be isolated from cutaneous specimens and can produce sulfur granules. These granules can be found in tissue specimens and can aid in detecting aerobic actinomycetes. To help identify the presence of sulfur granules in tissue specimens, which of the following methods will be most beneficial?

KOH Mount

A 65 y/o male with type 2 diabetes presented to ED complaining of febrile episodes following his last dialysis treatment. The microscopic examination of his urine showed numerous white blood cells and bacteria. His urine was sent to the laboratory for culture and sensitivity. Urine colony count was >100,000 CFU/mL for a single organism that was identified as Klebsiella pneumoniae. Observe the reactions of this organism on the Kirby Bauer antibiotic susceptibility plate and review the susceptibility results on the AST report form. The Hodge Test was positive. Which resistance mechanism is this organism demonstrating?

KPC - Klebsiella pneumoniae Carbapenemase

A 44-year-old female immigrant from Southeast Asia presented to the local clinic complaining of fever, chills, diarrhea and weakness. Patient history revealed that the woman worked in a research laboratory in her homeland. Her primary project was to develop an effective insecticide for the dreaded sandfly. The doctor decided to culture her blood for parasites. This form, measuring 14 µm, was recovered. The patient is most likely suffering from:

Kala-azar

In the image, what morphologic structure is shown in section D on this parasite form?

Karyosome

The small mass of chromatin located in the nucleus of the amebic parasites is termed:

Karyosome

The small beta hemolytic bacterial colonies growing on blood agar as shown in the upper photograph were recovered from an induced sputum specimen from a young child with pneumonia. The colonies were slow growing, small, entire and show soft beta hemolysis. Plump, Gram-negative coccobacilli, lying singly, in pairs and short chains, are seen on gram stain as illustrated in the lower photomicrograph. Most strains are chemically non-reactive except for a positive oxidase reaction and acid produced from dextrose and maltose. What is the name of the isolate?

Kingella kingae

Carbolfuchsin binds to mycolic acid in cell walls with high lipid/wax content and is retained after decolorizing, preventing counterstaining with methylene blue. This principle describes:

Kinyoun acid-fast staining

A sputum specimen submitted for culture is brick red in color. The organism causing this sputum color, also has a distinct polysaccharide capsule and is non motile. What organism can be associated with this sputum?

Klebsiella

Illustrated in this photograph, reading from left to right, are biochemical reactions for indole, Voges Proskauer, Simmons citrate, and Christensen's urea. The bacterial species providing the best fit for the reactions illustrated is:

Klebsiella oxytoca

Which of the following organisms is a lactose fermenter?

Klebsiella oxytoca

An 87-year old patient had a foot wound that grew gram-negative rods on McConkey agar as pink to dark pink oxidase-negative colonies along with the following results: TSI: A/AIndole: neg.MR: neg.VP: pos.Citrate: pos.H2S: neg.Urea: pos.Motility: neg.Ornithine: neg.Antibiotic susceptibility: Carboxicillin and ampicillin resistant, all others sensitive. What is the MOST likely organism?

Klebsiella pneumonia

A culture from a sputum specimen grew a mucoid, lactose fermenting organism. Biochemical testing on this isolate gave the following key reactions: VP: positive; Indole: negative; Urea: 1+, Motility: nonmotile, Citrate: positive. What is the most likely organism given the site of isolation and biochemical reactions?

Klebsiella pneumoniae

From the choices listed below, choose the most likely associated bacterial species represented in the image as pink, runny, mucoid colonies at 48 hours incubation on MacConkey (MAC).

Klebsiella pneumoniae

The distinctly large, spreading, mucoid colonies seen on blood agar in the upper left image, and the display of lactose fermentation on MacConkey agar in the upper right image provide for a presumptive organism identification. This species is most commonly recovered from respiratory specimens of patients with pneumonia. Observing absence of motility, a weak reaction for urea, and strong reactions for citrate and Voges-Proskauer confirm the presumptive identification. From the multiple choices, select the name of the isolate presented here.

Klebsiella pneumoniae

The reactions in a portion of the API strip, shown in the photograph, most closely identifies which organism?

Klebsiella pneumoniae

The top image shows a MacConkey agar plate on which mucoid, lactose fermenting colonies are present. The bottom image is the bacterial isolate streaked on the surface of a Mueller-Hinton agar plate. The disk to the left is ceftazadime, and the disk to the right is a combination of ceftazadime + clavulanic acid. Note the larger zone of inhibition around the combination disk on the right, an indicator for extended spectrum beta lactamase (ESBL) activity. Which of the following organisms fits this situation?

Klebsiella pneumoniae

This member of the Enterobacteriacea gave these reactions: H2S (TSI)Negative OrnithineNegative LysinePositive CitratePositive UreaPositive PhenylalanineNegative MotilityNegative What is this organism?

Klebsiella pneumoniae

What is the probable identity of an organism isolated from a wound culture that demonstrates the following test results? Phenylalanine Deaminase = negative TSI = A/A gas Citrate = positive Lysine = positive SIM = negative/negative/negative Urea = weakly positive

Klebsiella pneumoniae

Which of the following culture media should be used to attempt to recover mycobacteria from a clinical specimen?

Lowenstein-Jensen (LJ) medium

Erythema migrans, spirochetemia, and chronic arthritis are three stages in the progress of:

Lyme disease

The process of freeze drying of bacteria is called:

Lyophilization

Which of the following substances produced by Group A Streptococci is responsible for producing type specific immunity?

M antigen

All of the following are virulence factors utilized by Streptococcus pneumoniae to evade host defenses when causing meningitis, EXCEPT:

M protein

Pericarditis may occur as a complication from endocarditis caused by Staphylococcus aureus. Virulence mechanisms attributed to the spread of this organism include all of the following EXCEPT:

M protein

Which of the following Mycobacterium species is closely associated with infections in HIV positive patients?

M. avium-intracellulare complex

Which of the following species of Mycobacterium might be associated with contamination of the hot water system in large institutions such as hospitals?

M. xenopi

A microbiology laboratory recently purchased a rapid identification instrument that uses a laser on the microorganisms, which produces an ion cloud. These ions are then separated in a tube and travel within the tube to a detector. The time of travel will be measured and a mass spectrum will be produced. Which of the following techniques uses this methodology?

MALDI-TOF

Beyond direct detection, what molecular method listed below is being widely used in clinical laboratories across the United States and allows for rapid detection of a bacteria from an isolated colony?

MALDI-TOF

Conventional and molecular testing can both be used to identify Mycobacterium tuberculosis isolates. In fact, some molecular methods can test respiratory specimens directly without processing, which provides physicians with faster results when compared to conventional testing. When identifying Mycobacterium tuberculosis, all of the following methods can be used EXCEPT?

MALDI-TOF

Which of the following instruments is used for continuous monitoring of mycobacterial growth?

MGIT 960

Which of the following scenarios represents appropriate detection of MRSA by the Kirby Bauer method?

MHA; direct colony suspension; 35oC; cefoxitin disk; 18 hour incubation

Each of the following parasites, whose common names are listed, is associated with intestinal infections, EXCEPT:

Malayan filarial worm

The cellular immune response plays a role in whether a person exposed to Mycobacterium tuberculosis will develop tuberculosis disease (TB). Which of the following factors will make a person most at-risk of progressing from infection to active disease if exposed to M. tuberculosis?

Malnutrition

This Gram stain was prepared from a lower respiratory tract specimen. How should this Gram stain be reported?

Many gram-positive cocci in pairs, many polymorphonuclear white blood cells (PMNs)

All of the following agents can be handled using biosafety level 2 practices, EXCEPT:

Marburg virus

Matrix-assisted laser desorption-ionization time-of-flight (MALDI-TOF) is used for identification of aerobic bacterial isolates on a urine culture bench. Upon placing the target into the MALDI-TOF instrument, no peaks were found on any target spots, including the quality control. What caused this issue?

Matrix solution was not added to the target wells

The image represents:

Mature oocyst of Cytoisopora belli showing 2 sporoblasts

Which of the following life cycle stage is properly matched to it's location within the host?

Merozoites in erythorocytes

Illustrated in this photograph is an agar plate on which an unknown species has been inoculated. A 5 µg novobiocin disk (NB), a 100 µg furazolidone disk (FX), and a 0.04 µg bacitracin (A) disk had been applied immediately after inoculation of the plate. Based on the pattern of the zones of inhibition to these three antibiotics, the most likely identification is:

Micrococcus luteus

The bacterial species illustrated in these photographs was recovered from septic peritoneal fluid of a patient undergoing continuous peritoneal dialysis. The most likely identification is:

Micrococcus luteus

The surface of a blood agar plate after 48 hours, incubated at 37oC, shows colonies with smooth, lemon yellow pigmentation. Note in the image is a Gram stain with relatively large Gram positive cocci arranged in tetrads. Other distinguishing characteristics were the demonstration of susceptibility to bacitracin and resistance to furazolidone. Select the identification of this isolate.

Micrococcus luteus

Beginning with human infection, which of the following is the first stage of the Wuchereria bancrofti life cycle?

Microfilariae in blood or skin of humans

In the image to the right, identify the nuclear structure at the arrow of letter C.

Micronucleus

The calcofluor white stain can be used not only to help in the identification of fungi, but can be used to visualize which of the following?

Microsporidia

Illustrated are photomicrographs prepared from histological sections of a duodenal biopsy obtained from a patient with AIDS who was experiencing chronic diarrhea. Tiny intra-cytoplasmic spores are observed in both the left hand PAS stained and on the right Methylene blue-stained sections. The spores are best visualized in the PAS-stained section on the left (arrow). Stool specimens had been negative for parasites or bacterial pathogens. The acid-fast is negative with a positive Weber stain (Chromotrope 2R. Fast Green, phosphotungistic acid) confirming an identification. From the list of multiple choices, select the most probable presumptive identification.

Microsporidium species

Illustrated in the photomicrograph is a high-power view of the elements within a duodenal aspirate preparation using a Weber Stain (Chromotope 2R, Fast Green, phosphotungstic acid). This stain is used to identify the tiny 1.5 µm pink-red staining spores, many with central transverse septa as:

Microsporidium species

Illustrated in this photomicrograph is a silver-stained section of duodenal epithelial cells invaded by 1.5 µm in diameter spores (arrows). They appear red in the Weber-stained mounts (image not shown here). The presumptive identification is:

Microsporidium species

Under a Woods' lamp, infected hair strands from several children with tinea capitis showed green fluorescence, and subsequent cultures grew fungi with aerial mycelia and terminal chlamydospores. These isolates are most likely:

Microsporum audouinii

Which of the following organisms has been known to cause epidemic tinea capitis in children but almost never affects adults?

Microsporum audouinii

Illustrated in the photograph is a classic example of "ringworm" as may be observed in a young child, possibly contracted from the spores of an infected dog or cat. The identification of the dermatophyte causing this infection is illustrated in the lactophenol blue stained mount photomicrograph. Select the dermatophyte causing this type of infection.

Microsporum canis

An 18-year-old woman woke up in the morning to find that her left knee was hot, swollen, and very painful. She could not walk to work and a friend offered her a ride to the clinic. She had never had a swollen joint before. Physical exam revealed a tender knee joint which yielded purulent synovial fluid on aspiration. Gram negative intracellular diplococci were seen on Gram stain. She also had a cervical discharge that was cultured. The cause of her infection would grow best on:

Modified Thayer Martin (MTM) agar at 35º C with CO2

Each of the following tests is helpful in the species identification of Staphylococcus aureus EXCEPT:

Modified dimethyl sulfoxide (DMSO) test

Identification of intestinal microsporidial spores is usually done by using which of the listed stains?

Modified trichrome stain

All of the following are reasons why molecular methods for the detection of methicillin-resistant Staphylococcus aureus (MRSA) have gained increasing attention, except:

Molecular methods are less expensive than culture methods.

Which of the following best describes the benefits of the RPR or VDRL tests:

Monitoring course of treatment

A gram negative, oxidase-positive diplococcus was the predominant isolate from a sputum specimen of a patient with chronic obstructive pulmonary disease (COPD). Based on the reactions seen in the Quad-FERM system shown in the photograph, the most likely identification is:

Moraxella catarrhalis

A patient with an upper respiratory infection submits a sputum for culture. A gram stain performed on the sputum specimen reveals gram-negative diplococci. Oxidase testing is positive and carbohydrate degradation tests are inactive. What is the MOST likely identification?

Moraxella catarrhalis

All of the organisms below are known to cause gastroenteritis, EXCEPT:

Moraxella catarrhalis

The 48-hour growth of small pinpoint gray-white, smooth colonies on chocolate agar (right plate) are most commonly recovered as normal upper respiratory flora but may cause otitis media and sinusitis. There was no growth on Thayer Martin media (left plate). Growth on MacConkey agar is also absent. Short, plump, Gram negative cocci lying singly and in loose clusters are seen in Gram stain, as illustrated in the lower photomicrograph. This non-fermenter is non-motile, oxidase positive, and does not utilize carbohydrates (assacharolytic). Nitrates are reduced and DNAse is positive. From these observations, select from the multiple choices the presumptive identification of this isolate.

Moraxella catarrhalis

The purulent exudate and the intracellular bacteria (shown by the arrows) as illustrated in this photograph to the right was observed in a direct sputum gram stain of a 70 year-old patient with chronic obstructive pulmonary disease. Which bacterial species most likely grew out in culture?

Moraxella catarrhalis

Which of the following has been compared to a hockey puck when discussing its morphology on chocolate agar?

Moraxella catarrhalis

Which of the following organisms are aerobic, Gram negative diplococci that do not ferment sugars and is DNAse positive?

Moraxella catarrhalis

A culture was taken of a conjunctival exudate. The bacterial species, represented by the tiny colonies seen on this chocolate agar plate were recovered after 48 hours incubation at 35°C. The isolate was cytochrome oxidase positive and highly susceptible to penicillin. What is the most likely identification of this organism?

Moraxella lacunata

Sequence-based testing is most useful in identifying which of the following organisms?

Mycobacterium

Which of the following would ensure positive patient identification prior to specimen collection?

Patient's full name and hospital or medical record number.

A patient shows signs of conjunctivitis including itching of the eyes, reddening of the conjunctiva, purulent secretion and lid edema. A culture was taken of the secretion and a Gram negative coccobacilli was seen on both the Sheep's blood and chocolate agars. There was no growth observed on the MacConkey agar. Additionally, the colonies were oxidase positive, catalase positive, reduced nitrate to nitrite, and liquefied gelatin. The identification of this organism is:

Moraxella lacunata

Tiny translucent gray colonies were recovered on blood agar from a patient with purulent conjunctivitis. Gram negative diplococci were seen on Gram stain. The preparation illustrated in this photomicrograph was obtained from colonies growing at the margin of inhibition of a 10 µg/mL penicillin disk. The most likely identification is:

Moraxella lacunata

The colonies shown in this 5% sheep blood agar (left) and MacConkey agar (right) split frame photograph are most likely those of:

Morganella morganii

A tech is working with a large, spore-forming, Gram-positive bacillus that they believe is Bacillus spp. Which of the following tests could the tech use to ensure this organism is not Bacillus anthracis?

Motility positive

Each of the following characteristics is prerequisite for a bacterial species to be classified within the family Enterobacteriaceae except:

Motility via peritrichous flagellae

Illustrated in the top photograph is a 3 day old colony incubated at 30o C, with a border to border white hair-like mycelium with peripheral borders of brown and brown-black pigmentation. Although consistent with one of the Zygomycetes, a genus/species identification cannot be made. Observed in the high power photomicrograph is a lactophenol blue stained mount of a fruiting head in which a non-septate hypha terminates in a bulbous columella (arrow) that extends into a spherical sporangiophore. Rhizoids were not observed. From these observations, select from the multiple choices the name of this isolate.

Mucor species

The following are described as rapid growing, opportunistic fungi that are differentiated based on the presence of sporangiospores, the shape of the columella, presence or absence of rhizoids, and the location of the rhizoids on the stolon.

Mucorales species

Which of the following media is commonly used when performing the Kirby-Bauer disk diffusion?

Mueller-Hinton agar

Which molecular methodology is used to detect multiple targets in a single sample of CSF when meningitis/encephalitis is suspected?

Multiplex PCR

What causes the hemolysis associated with infection by malaria organisms?

Multiplication of merozoites within erythrocytes

Which of the following distinguishing characteristic is associated with Streptomyces species?

Musty basement odor

Illustrated in the photograph are 14-day-old colonies of a Mycobacterium species growing on Middlebrook 7H10 agar, with development of yellow pigmentation after exposure to environmental light. From the choices listed below, select the correct presumptive identification of this photochromogenic Mycobacterium species.

Mycobacerium marinum

The images show disease presentations associated with Mycobacterium species infections. Which organism correlates to the disease presentation seen in the lower right image?

Mycobacerium scrofulaceum

The organism cultured on the Lowenstein-Jensen agar slant shown in the image to the right is most likely:

Mycobacteria

Several patients developed subcutaneous abscesses at the sites of injection of a preparation labeled "adrenal cortex injection" administered as part of a weight loss regimen. Pale-staining, filamentous acid-fast bacilli were seen in the material aspirated from the lesions (the upper photomicrograph is representative) and the colonies shown in the lower photograph grew out after 3 days incubation at 35°C in CO2. The most likely identification is:

Mycobacterium abscessus

Which of the following is the most common cause of nontuberculous mycobacteria (NTM) lung disease?

Mycobacterium avium complex (MAC)

Small, gray-white colonies, growing on 7-H10 agar as illustrated in the upper left image, were recovered from an upper respiratory specimen after 7 days of incubation. This Mycobacterium species in the past was not often recovered from human infections until the discovery of AIDS when it became an agent of pulmonary infections, as well as other systemic infections. Most notably, the colony isolates exhibit a pale yellow pigmentation that does not intensify with light exposure (see upper right image). These acid-fast bacilli illustrated in the lower image are short and found singly or in loose clusters. From these observations, what is the MOST likely identification?

Mycobacterium avium/intracellulare

Which Mycobacterium sp. causes the infectious disease tuberculosis (TB)?

Mycobacterium bovis

Which Mycobacterium species will have a negative result for niacin, nitrate reduction, Tween hydrolysis (5 days), and iron uptake?

Mycobacterium bovis

Which organism will infect humans and a wide range of host animals?

Mycobacterium bovis

The tiny colonies growing on chocolate agar after 3 days incubation, as illustrated in the left plate in the upper photograph, were recovered from a skin abscess at the site of a contaminated needle injection. The colonies growing on Middlebrook 7H10 agar seen to the right in the image were larger, smooth, convex, and gray-white. Acid fast stains were positive for the appearance of slender bacilli, consistent with one of the rapidly growing Mycobacteria. Reactions for nitrate reduction and iron uptake were negative. A distinctive characteristic was the antibiotic resistance to Ciprofloxacin (left upper strip) and Polymyxin B susceptiblility (vertical strip) in the lower photograph. From these observations, select the identification of this isolate.

Mycobacterium chelonae

A three-year-old female was seen by a local ear, nose and throat specialist for chronic ear pain. She had been treated several times for otitis media by her pediatrician with no resolution. Drainage from her ear grew an acid fast bacillus that gave the following biochemical reactions:Iron Uptake- Positive Nitrate reduction- Positive Arylsulfatase - Positive MacConkey agar growth, 5 days- Positive It should be identified as:

Mycobacterium fortuitum

An acid-fast bacillus recovered from a post-surgery wound of a young child had the following characteristics: Rapid growth (3-5 days) on blood and chocolate agar Nitrate positive Niacin negative Urease positive Catalase 68ºC positive Iron uptake positive Which of the following Mycobacterium species does this represent?

Mycobacterium fortuitum

From the choices listed below, select the name of the acid-fast bacillus that can be presumptively identified by observing smooth, waxy, light gray-white colonies with rapid growth on Middlebrook 7H11 agar within 3 - 5 days of incubation. The nitrate reduction reaction was found to be positive.

Mycobacterium fortuitum

Illustrated in the upper left image in the composite photograph are 5-day old gray-white colonies growing on 7H10 agar. The acid-fast stain shown at the lower left reveals short, thick, acid-fast bacilli with filamentous forms. The micro-colony as microscopically observed on Lowenstein Jensen medium as illustrated in the photomicrograph at the upper right. A positive iron assimilation test is shown in the lower right image by the appearance of black pigment on a colony growing on a Lowenstein Jensen slant following an additional 2 days incubation where drops of ferric ammonium citrate had been added to the growing colony. With these observations, select from the multiple choices the identification of the Mycobacterium species presented in this exercise.

Mycobacterium fortuitum

MacConkey agar without crystal violet is a culture medium useful in the presumptive identification of:

Mycobacterium fortuitum

The Mycobacterium species capable of growing on modified MacConkey agar (crystal violet removed from the formula), as illustrated in this photograph, is:

Mycobacterium fortuitum

All of the following Mycobaterium species produce pigments, EXCEPT?

Mycobacterium fortuitum group

Which Mycobacterium species has the shortest growing time on agar media when recovered from clinical specimens?

Mycobacterium fortuitum/chelonae

The entire, smooth, convex Mycobacterium species colonies growing on 7H10 agar were observed to be dark yellow pigmented early in culture even before having been exposed to light. This isolate was found to be Tween-80 positive as seen in the reaction tubes in the bottom photograph. Select from the multiple choices the presumptive identification of this isolate:

Mycobacterium gordonae

Illustrated in this exercise are colonies growing on Middlebrook 7H10 agar before (lower) and after (upper) exposure to light. Colonies are intermediate between smooth and rough depending on the strain. Prior to light exposure, the colonies are gray white. Upon exposure to ambient light, visible yellow pigment production is observed characteristic of one of the "photochromogens", as illustrated in the top composite colony photograph. The acid-fast stain reveals slender acid fast bacilli with cross banding. Characteristic for this isolate are positive reactions for several biochemical reactions - nitrate reduction, Tween 80 hydrolysis, catalase, and urease. With these observations, select the species name of this isolate.

Mycobacterium kansasii

Illustrated in this photograph are two Middlebrook 7H-11 plates incubated at 35°C, on which are growing colonies of an unknown Mycobacterium species. The plate on the left was incubated in the dark; the plate on the right had been exposed to light for 24 hours. The most likely identification is:

Mycobacterium kansasii

What is the MOST likely identification of an acid-fast bacillus that demonstrates the following characteristics? Slow growth Cream to tan colored colonies when grown in the dark Development of yellow pigment upon exposure to light

Mycobacterium kansasii

Which of the following is the most likely identification of an acid fast bacilli recovered from an induced sputum with these culture findings? Slow growth at 37o CNiacin test = negativePigmented photochromogenicNitrate test = positiveCatalase = positive

Mycobacterium kansasii

All of the following Mycobacterium species will cause tuberculosis, EXCEPT?

Mycobacterium leprae

Which of the following causative agents is most likely associated with the "swimming pool granualoma" skin lesions depicted in the attached photograph?

Mycobacterium marinum

The accumulation of niacin, as shown by the yellow reaction on the test strip shown in the right tube is one of the chief characteristics to identify Mycobacterium tuberculosis. Another rarely encountered Mycobacterium species that also accumulates niacin is:

Mycobacterium simiae

A 67-year-old homeless man was seen in the ambulatory clinic for chest pain and sputum production. A mycobacterial culture showed the following: rough, non-pigmented colonies, which grew after two weeks at 35oC and failed to grow at other temperatures, serpentine cording, a strongly positive niacin test, nitrate reduction, and loss of catalase activity after heating at 68oC in pH 7. What is the most likely identification?

Mycobacterium tuberculosis

Illustrated in the top image are 10 day old rough, buff, gray-white colonies growing on Middlebrook 7H11 agar. These colonies are commonly recovered from expectorated or induced sputum specimens obtained from patients with signs and symptoms of pneumonia. The appearance of these colonies provide for a presumptive identification, supported by the positive yellow-pigmented niacin reaction seen in the reagent tube in the lower photograph. From these observations, select from the multiple choices the presumptive identification of this isolate.

Mycobacterium tuberculosis

Illustrated in the top photograph are acid-fast bacilli as they may appear in acid-fast stains prepared from a direct mount of infected tissue. These acid fast bacilli are thin, slightly curved, red-pigmented and beaded. The acid fast bacilli, as illustrated in the bottom photograph, aggregate in serpentine chords in stained mounts prepared from colonies growing on agar. From these observations, select the presumptive identification of this mycobacterium.

Mycobacterium tuberculosis

The following is the MOST likely identity of an acid-fast bacilli that showed buff colored, dry, heaped colonies; niacin, nitrate, and urease positive; and took 23 days at 35ºC to grow:

Mycobacterium tuberculosis

Routine culture methods in microbiology rely on the principles of bacterial cultivation and identification. Molecular testing, however, relies on the detection and manipulation of nucleic acids, allowing the microbial genes to be detected instead of the analysis of microbial products (for e.g. enzymes, toxins or identifiable characteristic growth of an organism). One disadvantage to doing molecular testing is?

Need for dedicated space and equipment

Critical results from the microbiology department must be communicated to the clinician immediately. All of the following results are considered critical EXCEPT?

Negative acid-fast stain

All of the following observations are consistent with the laboratory identification of Cryptococcus neoformans, EXCEPT:

Negative urease test.

The oxidase test is used to presumptively identify which of these organisms?

Neisseria

A Gram negative diplococci grows on MTM (Modified Thayer Martin), is oxidase positive and superoxol positive. The carbohydrate utilization reaction seen in the QuadFerm system shown in the image provides an identification of which of the following organisms?

Neisseria gonorrhoeae

A joint fluid was received in the microbiology laboratory. The specimen was cloudy and many neutrophils with intracellular and extracellular Gram negative diplococci were seen on the Gram stain. The specimen was inoculated to sheep blood and chocolate agar and grew a small, grayish white colony on chocolate with no growth observed on the sheep blood. Which of the following is most likely the organism?

Neisseria gonorrhoeae

From the list of organisms below, identify the most likely species based on this image of a gram stain from a male urethral swab.

Neisseria gonorrhoeae

Illustrated in the upper photograph are smooth, entire, convex gray-yellow pigmented 48-hour old colonies growing on the surface of Thayer Martin medium. These isolates may be observed in cultures of specimens received from a physician's office obtained from patients with endocervicitis in females or urethral epididymitis in males. Illustrated in the lower photomicrograph is a gram stain prepared from the sediment of the specimen. These observations are enough to make a presumptive identification of Neisseria species. Further testing revealed the characteristic selective carbohydrate utilization of glucose with maltose utilization being negative. Select the identification of this isolate.

Neisseria gonorrhoeae

Sexually active women can develop peritonitis in the form of perihepatitis, inflammation of the liver surface, due to which of the following organisms?

Neisseria gonorrhoeae

The Thayer-Martin agar plate seen in this illustration exhibits marked growth. The most likely organism found here would be:

Neisseria gonorrhoeae

The most common organism that causes septic arthritis in patients under 30 years of age is:

Neisseria gonorrhoeae

A gram-negative diplococcus is isolated from a throat culture. The isolate grows on Thayer-Martin agar, produces acid from maltose, lactose, and glucose and is ONPG positive. What is the most likely identification of this isolate?

Neisseria lactamica

A patient came into the emergency department with symptoms of meningitis. The patient was suspected of having a blocked cerebral shunt, which can cause meningitis. The shunt was drained and sent to the microbiology laboratory for culture. All of the following organisms are associated with shunt infections EXCEPT?

Neisseria meningitidis

An organism grew out of a spinal shunt. The protocol for growth of this organism is to notify infection control and the public health department. In addition, any health care worker who came in contact with the patient must be treated promptly with antibiotic prophylaxis. Which of the following organisms requires this type of protocol?

Neisseria meningitidis

Small intracellular gram-negative cocci were observed in a centrifuged spinal fluid sediment as presented in the upper photomicrograph. A clinical diagnosis of meningitis was suspected. Yellow-gray colonies after 24-hour incubation had been observed on blood agar. Based on the carbohydrate utilization tube reactions observed in the lower photograph, what is the presumptive identification of this isolate.

Neisseria meningitidis

The bacterial species shown in this composite photograph of a chocolate agar plate and accompanying gram stain, recovered from an autopsy blood culture of a patient dying with Waterhouse Friderichsen syndrome is most likely:

Neisseria meningitidis

The following are all possible causes of cell death in HIV infections, EXCEPT?

Penetration of the membrane by the HIV spike

The dry, chalky, indented, gray-yellow colonies growing in five days on chocolate agar as illustrated in the upper image were recovered from an expectorated sputum sample of a patient with bronchopneumonia. Illustrated in the lower image are delicate, branching bacilli, which are modified (partial) acid-fast positive (pink). They are also full acid fast stain negative. Key to the identification is negative hydrolysis of casein, tyrosine, and xanthine on casein agar. With these observations, what is the genus/species identification of this isolate?

Nocardia asteroides

The following organism is described as a branching Gram-positive bacillus that is partially acid-fast and able to hydrolyze urea, but unable to hydrolyze casein, xanthine, or tyrosine.

Nocardia asteroides

A 30-year-old woman developed progressive, painful swelling of the right foot after incurring traumatic penetration of the soft tissue by a splinter. The wound initially healed. The upper photograph is a direct Gram stain of purulent material expressed from a sinus tract. The lower photograph illustrates the colony that grew out in 72 hours, which had a "musty" odor. The most likely identification is:

Nocardia brasiliensis

Illustrated in the top photograph are dry, chalky, heaped colonies growing on Middlebrook agar with a distinctive yellow-orange pigmentation. They were recovered after 5 days incubation from a subcutaneous lesion of the foot from a South American field laborer. Illustrated in the acid-fast stain in the lower photomicrograph are slender, branching acid-fast bacilli. Casein and tyrosine were hydrolyzed. With these observations and reactions, select the species identification of this isolate.

Nocardia brasiliensis

Light yellow, wrinkled, hemolytic colonies resembling an aerobic actinomycetes were observed on sheep blood agar. The gram stain, showing gram-positive bacilli, with branching, beaded rods were seen. Key to the identification is the hydrolysis of casein, as seen in the lower photograph. Acetamide was not hydrolyzed. The presumptive identification is:

Nocardia brasiliensis

Which of the following organisms is a cause of cutaneous infections?

Nocardia brasiliensis

The following aerobic, branching, filamentous gram-positive species is weakly acid fast and known to cause mycetomas and lung infections in immunocompromised individuals:

Nocardia species

Which of the following organisms is an acid-fast aerobic actinomycete?

Nocardia spp.

All of the following are characteristic of Burkholderia pseudomallei EXCEPT?

Non-motile

Shigella species generally exhibit which of these characteristics?

Non-motile

Examine the Oxidation and Fermentation media images to the right. The image labeled as Bucket A represents what type of organism?

Non-utilizer

This suspicious form, recovered in stool, measures 12 µm in length. Which of the following conditions is this form responsible for causing when present?

None; considered non-pathogenic

This suspicious form is associated with which of the following conditions?

None; pseudoparasite

A CSF specimen was sent to the laboratory for analysis. A glucose, protein, and cell count were performed. Based on the following results, what would be the probable cause? AnalyteResultGlucose50 mg/dLProtein25 mg/dLLeukocytes2 cells/mm3

Normal CSF

When a corrected report needs to be made, which of the following is required?

Notify the physician of the erroneous report

The following steps were used in a procedure to identify M. kansasii:

Nucleic acid probes

The stage of Ixodes tick most likely to transmit Lyme disease is:

Nymph

In the Escherichia coli 0157:H7 serotype. The 0157 portion of the serotype refers to which of the following?

O somatic antigen

Bacteria which require oxygen for proper growth are termed:

Obligate aerobes

Which of the following is the first step in the four steps of Koch's postulates?

Observe the same organism in all cases of a given disease

MacConkey agar contains all of the following except:

Penicillin

The colonies growing on blood agar, illustrated in the top image, are small, convex, entire, smooth, and light-yellow pigmented. Gram stain revealed short gram-positive bacilli arranged in loose clusters. Key to the identification is the positive lecithinase activity on egg yolk agar (lower image). Catalase and oxidase reactions were found to be positive and acid was produced from most carbohydrates. This is a soil organism occasionally causing nosocomial infections related to exposure to contaminated water. From these observations, select the presumptive identification of this isolate.

Oerskovia xanthineolytica

Enterococcus faecium is:

Often vancomycin resistant

Malassezia furfur is the cause of tinea versicolor. To cultivate this organism, the agar should be overlaid with:

Olive oil

What is the main problem with the acridine orange stain?

Once a bacterium is detected, a Gram stain must be used to determine differential staining characteristics.

Illustrated in the upper photograph is a 15-year-old native of Guatemala who presents with a 20 mm elevated skin nodule of the right forehead. A Giemsa-stained mount of aspirated fluid from within the nodule is shown in the lower image. From the appearance of the skin lesion and the microfilaria seen in the microscopic mount, select from the multiple choices the presumptive clinical and laboratory diagnosis.

Onchocerca volvulus

Which one of the following parasites gives birth to live larvae known as microfilariae?

Onchocerca volvulus

This suspicious form was recovered from a nodule biopsy. It measures 300 µm in length and lacks a sheath. Identify the suspicious form.

Onchocerca volvulus microfilaria

Which EBV markers would be MOST likely positive for an individual who had infectious mononucleosis nine years ago?

Only anti-VCA (IgG) and anti-Epstein-Barr nuclear antigen (EBNA) are positive.

Which one of the following results is typical of Campylobacter jejuni?

Optimal growth at 42 ºC

Which of the following tests would be most useful in the identification of Streptococcus pneumoniae?

Optochin

Which of the following tests should be incubated at 37º C in a 5-10% CO2 atmosphere?

Optochin disk test

A 25-year-old female patient suspects of having an urinary tract infection (UTI) and presents to her doctor for a check-up. Her urine specimen is slightly turbid and the chemical and microscopic urinalysis results are as follows: Specific Gravity1.009Glucose0pH8Protein1+WBC15/hpfRCS1/hpfCrystalsNoneCasts2 hyaline/hpfEpithelial cells0/hpfBacteria2+ What should her doctor do next?

Order a culture and sensitivity

What is one of the BIGGEST challenges with isolating Francisella?

Organism growth is slow.

Name the morphologic structure labeled 'C' on this parasite form:

Outer cell wall

A wound specimen was received into the laboratory and a large Gram positive rod was isolated. The microbiologist suspected the isolate was a probable Bacillus anthracis and had to rule in/out before reporting. All of the following tests must be performed before calling the species Bacillus anthracis EXCEPT?

Oxidase

A tech is working with a small Gram-negative coccobacillus that may be Burkholderia pseudomallei. Which of the following tests could the tech use to rule out this organism?

Oxidase negative

Acinetobacter spp. are similar to Neisseria spp. EXCEPT Acinetobacter spp. are generally:

Oxidase negative

All of the following are characteristics of Brucella are EXCEPT:

Oxidase negative

The following is the BEST test to differentiate between Aeromonas hydrophila and Escherichia coli from a wound culture:

Oxidase production

The bacterial species producing the set of reactions seen in the oxidative/fermentative (OF) glucose tubes illustrated in this photograph at the right is a (an):

Oxidizer

Multiple ring forms in one red blood cell are most frequently seen in which Plasmodium species infections?

P. falciparum

Oxacillin resistance of MRSA is due to production of which of the following penicillin binding proteins (PBPs)?

PBP2a

Which of the following is a rapid latex agglutination method for detecting Methicillin-Resistant Staphylococcus aureus (MRSA)?

PBP2a

The 10-day-old colonies grown on SABHI agar incubated at 30° C as illustrated in the top photograph are characteristic of those recovered from skin nodules of workers living in South America, especially Brazil. Although a dimorphic fungus might be suspected from the appearance of the slow-growing, gray white, cob-web like colonies, the final identification can be confirmed by observing the microscopic appearance of tease mounts prepared from the surface mycelium, as observed the bottom photograph. Based on these descriptions, what is the most likely identification?

Paracoccidioides brasiliensis

The colonies observed on the agar surface in the top photograph represent 4 day-old yeast colonies converted from a mold colony suspicious for a dimorphic fungus. The identification is made by microscopically observing the characteristic morphology of the yeast cells as illustrated in the bottom photomicrograph. What is this species?

Paracoccidioides brasiliensis

The yeast forms of which of the following species of dimorphic fungi (represented in the image on the right) can be described as large yeast cells with multiple buds that are attached by narrow necks, giving the appearance of a "mariner's wheel?"

Paracoccidioides brasiliensis

Which of the following adult parasites are found in the lungs and the eggs are most commonly recovered in sputum samples?

Paragonimus spp.

A 38-year-old male presented to the E.R. complaining of severe cough, chest pain, shortness of breath, and general fatigue. Parasitic examination of his bloody sputum revealed this suspicious form. The patient is most likely suffering from:

Paragonimus westermani

The adult fluke related to the 100 µm ovum, as illustrated in the image shown, most commonly inhabits the lung parenchyma. The ovum, as may be observed in a sputum specimen, has a smooth, slightly thickened shell with a prominent shouldered operculum as seen at the left lower end. A developing larva is observed within, retracting from the inner margin of the shell leaving a clear space. Infections with this fluke are endemic in the orient, in West Africa, in South and Central America and may be observed in patients elsewhere after travel to one of these regions. Humans become infected after ingestion of poorly cooked crab meat or crayfish contaminated with metacercariae. Intermittent chest pain, and cough with occasional spitting up of blood (hemoptysis) may be experienced after infection. From the choices below, select the trematode species related to this ovum.

Paragonimus westermani

Recovered from a sputum sample, this suspicious form measures 112 µm by 55 µm. What is the organism?

Paragonimus westermani egg

The image to the right was recovered from a sputum sample. The form in the image measured 112 µm by 55 µm. Which of the following is the correct identification?

Paragonimus westermani egg

Which of the following parasites migrate either to or through the lungs in their corresponding life cycle?

Paragonimus westermanni

The presence of parasites in human blood is termed:

Parasitemia

All of the following organisms are considered select agents for a bioterrorism event, EXCEPT?

Parasites

The FilmArray meningitis/encephalitis panel is a multiplex panel that detects all of the following microorganism types, EXCEPT?

Parasites

The episodes of fever and chills experienced by patients suffering from malaria are known as:

Paroxysms

Infections of the bone marrow are not only caused by bacteria and fungi, they can be caused by viruses as well. Which of the following viruses can often be isolated from bone marrow specimens?

Parvovirus B19

Which of the following viruses is MOST often reported as the cause of infection leading to aplastic crisis in a patient with sickle cell disease?

Parvovirus B19

The colonies illustrated in the upper photograph, recovered from a cat bite skin lesion of a child, reveal good growth of entire, convex, gray-white, smooth colonies on blood and chocolate agars. The colonies on blood agar are non-hemolytic and growth was not observed on MacConkey agar. Coccoid to rod-shaped Gram-negative bacilli are observed in the Gram stain. Positive tube reactions for indole, Voges Proskauer, ornithine, arginine, and strong production of esculin are observed in the lower photograph. The cytochrome oxidase reaction is also positive. With these observations, select the best choice for the identification of this isolate.

Pasteurella multocida

The upper image of a blood agar plate illustrates the smooth, gray, nonhemolytic colonies that were recovered after 36 hours incubation from a wound of the forearm of a 14-year-old boy following a dog bite. The colony had a musty or mushroom odor and is oxidase positive. It did not grow on MacConkey agar. The lower image illustrates the gram stain prepared from the colony. The most likely identification is:

Pasteurella multocida

Illustrated in the top image is a 4-day growth of a dark brown, entire colony with a narrow outer white zone. The surface mycelium is glabrous and finely granular. As this colony is not specific, the fungal species identification must be made on stained mounts prepared from the surface of the mycelium. In the lactophenol blue mount shown in the bottom photomicrograph is the characteristic sac-like structure, a pycnidium, within which are contained small spiral, hyaline, one-celled conidia. Select the name of the fungal species represented in these photographs.

Phoma species

Refer to the image on the right demonstrating macroscopic images of hyaline molds. All of the following are accurate descriptions of the expected microscopic findings, EXCEPT:

Photo A: single-celled, smooth walled microconidia

Immunosuppressed or diabetic patients with ketoacidosis may present with symptoms of a brain abscess caused by which of the following?

Phycomycosis

All of the following may cause systemic mycoses EXCEPT:

Piedraia hortae

Which animal was involved in the reassortment of influenza A viruses that led to the 2009 novel influenza A H1N1 virus?

Pigs

Host cells (e.g., white blood cells, epithelial cells) will appear what color on a properly stained Gram stain?

Pink

Based on the picture and the criteria below, how would the Gram stain be interpreted? Host cells and background materialpink | blueSmear thickness1 cell thick or > 1 cell thickPrecipitated stainyes | noWould this field be appropriate for reading?yes | no????

Pink, 1 cell thick, No, Yes

What is the unique colony morphology feature of Rhodotorula growing on Sabouraud Dextrose Agar (SDA)?

Pink-red/orange pigment

What is the common name of this parasite that has eggs such as those in the picture to the right, measuring 50 µm by 30 µm?

Pinworm

Perianal itching is the major symptom of infection with both forms of the organism pictured here. This parasite is the causative agent of what condition?

Pinworm infection

A tech is working on a urine culture and notices that the agar plates are not streaked properly. The tech decides that that culture must be reset. Where should the tech document this finding and the actions taken?

Place all notes in the culture work card

You are processing a Level 1 specimen for culture when two other specimens arrive for processing. The two specimens are: Sputum for sputum culture Urine in a boric acid transport tube for urine culture How would you handle the processing of these two new specimens?

Place the sputum culture in the refrigerator, leave the urine at room temperature, and continue processing the Level 1 specimen

To enhance recovery of bacteria, proper inoculation of broth media may be accomplished by:

Placing a few drops of liquid specimen directly into the tube of broth

An 85-year-old female nursing home patient was treated empirically with a cephalosporin for a urinary tract infection, but later failed therapy. The physician then requested a culture and sensitivity on a new urine specimen which grew >100,000 CFU/mL of Escherichia coli. After reviewing the Kirby-Bauer disc susceptibility plate and susceptibility interpretations, what is the resistance mechanism (if any) for this organism?

Plasmid-mediated AmpC

A 40-year-old business man developed intermittent spiking fevers one week following a trip to Western Africa. The Wright-stained peripheral blood smear as illustrated in the image was observed. Based on the morphology of the erythrocytes and the heavy invasion with ring form trophozoites, the diagnosis of malaria could be made. With particular focus on the sickle-form gametocyte, which Plasmodium species is represented by this peripheral blood smear?

Plasmodium falciparum

The diagram indicates the banana-shaped gametocyte of the following Plasmodium species? The correct answ

Plasmodium falciparum

These forms may be observed when screening through a peripheral blood smear. Closer observation of Giemsa-stained smears shows erythrocytes infested with a malarial parasite (upper center). Note the peripheral location of tiny ring forms immediately beneath the red cell membrane. From the multiple choices listed, select the most likely species identification.

Plasmodium falciparum

This image depicts a blood smear made from a patient with symptoms resembling malaria. Please identify the species listed below that matches the parasite forms shown in the image with arrows.

Plasmodium falciparum

Which Plasmodium species tends to infect any red blood cell, regardless of the age of the cell?

Plasmodium falciparum

Which malaria pathogen is associated with massive hemolysis, blackwater fever, and blockage of capillaries?

Plasmodium falciparum

Which type of Plasmodium infection will have severe anemia, is very common to have CNS involvement, and has a 6-17-month duration for an untreated infection?

Plasmodium falciparum

This parasite assumes a characteristic banana shape and grows inside red blood cells until it eventually destroys the cells. What is the MOST likely identification and stage?

Plasmodium falciparum gametocytes

The reactions observed in this Kligler Iron Agar slant (left) and Christensen's urease slant (right) provide the presumptive identification of:

Proteus mirabilis

Which of the following stool pathogens would demonstrate the following reactions: TSI: A/A with H2S production LIA: R/A

Proteus spp.

Babesia is a parasitic organism that morphologically resembles which of the following?

Plasmodium falciparum rings

All of the organisms are listed with a common site of recovery for that parasite, EXCEPT:

Plasmodium falciperum - ocular secretions

Patients with a diagnosis of malaria who have fever spikes less frequently, spanning three or four days, are said to have "quartan malaria". Illustrated in the high power upper photomicrograph is a stained peripheral blood smear. Note the infected red blood cell that contains a developing trophozoite that distinctively "bridge" between the opposite erythrocyte membranes. The lower photomicrograph illustrates the schizont stage of development in which segments are arranged as a rosette around a central aggregate of malarial pigment. Which of the Plasmodium species is represented in this scenario?

Plasmodium malariae

Which type of Plasmodium infection has a 72-hour cycle, tends to infect old cells, and will have normal sized red blood cells?

Plasmodium malariae

Which malarial species schizont is found inside red blood cells that typically contain 6 to 12 merozoites with a central brown/green pigmented mass and sometimes forms rosette shapes?

Plasmodium malariae schizont

The high power photomicrograph is of a stained peripheral blood smear that includes two erythrocytes that are infected with malarial parasites. This infection commonly does not involve humans. Based on this microscopic observation, select the species identification from the multiple choices listed below.

Plasmodium ovale

The picture best represents the following:

Plasmodium ring form

This parasite was found on a Giemsa stained blood smear. The form shown in the image at the arrow is best described as:

Plasmodium ring form

A blood smear demonstrates the suspicious form in this illustration. The most likely identification is:

Plasmodium schizont

This image was taken from a individual suffering from a severe organism-related anemia. Which organism could have caused this patient's anemia?

Plasmodium sp.

Thick Giemsa-stained blood smears are primarily used to screen for the presence of:

Plasmodium species

Which of the following red blood cell inclusions is seen in the photomicrograph (arrow)?

Plasmodium species intracellular ring form

Illustrated in the image of a Wright-stained peripheral blood smear is a developing intra-erythrocyte schizont. In review of this presentation, select from the multiple choices listed below the Plasmodium species represented by the image as shown.

Plasmodium vivax

Presented in the photomicrograph is a close-in view of an enlarged erythrocyte infested with a malarial trophozoite. Which Plasmodium species is represented with these characteristics?

Plasmodium vivax

Which malarial parasite is most likely present in a patient with a stained blood smear that reveals giant platelets, many reticulocytes containing Schuffner's dots, large ring forms, and schizonts with 12-24 merozoites?

Plasmodium vivax

The cytochrome oxidase-positive bacterial species that is DNAse negative, ornithine decarboxylase positive, and is associated with gastroenteritis in children after the ingestion of contaminated water is most likely:

Plesiomonas shigelloides

Which of the following species is an oxidase-positive, glucose-fermenting, Gram-negative bacilli?

Plesiomonas shigelloides

In this photomicrograph, several dematiaceous hyphae with long, flask-shaped, tapered phialides that have flat saucer-like terminus are seen (arrow). This feature is most characteristic of which of the following fungal species?

Pleurostomophora richardsiae

Immunocompromised patients, such as those with Acquired Immunodeficiency Syndrome (AIDS) are at an increased risk of contracting an unusual form of pneumonia from which of the following microorganisms?

Pneumocystis jiroveci (carinii)

The antiphagocytic capsule of Streptococcus pneumoniae is composed of:

Polysaccharides

Which of the following is considered the best fixative for maintaining specimen integrity during and following permanent staining of ova and parasites?

Polyvinyl alcohol (PVA)

A bone biopsy from a jaw sent to a microbiology laboratory for culture grew out an Actinomyces species. What would be the most probable contributing factor to this infection?

Poor oral hygiene

The condition most likely to predispose a person to septicemia by viridans streptococci is:

Poor oral hygiene

Consider the following matches of parasites with their common names. Each is a correct match EXCEPT:

Pork tapeworm =Taenia saginata

The colonies illustrated in the composite blood agar/MacConkey agar to the left were recovered from an inflammatory infection of the oral cavity of a 16-year-old student. The colonies on both agar plates incubated anaerobically are small, entire, and smooth with a light gray-yellow pigmentation. Small gram-negative rods arranged singly and in loose clusters had been observed microscopically in a gram-stained preparation. Spot indole and lipase reactions are positive. Note in the image to the right the alk/alk non-fermentative carbohydrate reaction on Kligler Iron agar, with lack of fermentation of the sugars presented in the tubes to the right (asaccharolytic). Select from the multiple choices the name of this anaerobic, asaccharolytic, gram-negative isolate.

Porphyromonas asaccharolytica

A tech working in microbiology has reported the following results throughout their workday. Which of the result would be considered an urgent alert value that must be called to the physician?

Positive acid fast smear

From the following instances that may occur in the microbiology laboratory, which one is a critical result requiring immediate communication to the healthcare provider?

Positive acid-fast smear from a bottle for mycobacterial blood culture

The tech is working in microbiology and typically, there is an automatic call list generated by the laboratory information system (LIS) for urgent microbiology alerts. The LIS is currently down for maintenance so the tech has to manually pull a list of urgent reports. Which of the following should the tech considered an urgent result?

Positive blood culture showing Gram positive cocci

Interpret the auramine fluorochrome stain image to the right:

Positive for acid-fast bacilli

A nitrate test is performed on a glucose nonfermenter. When the nitrate reagents were added, no color change occurrs. When zinc dust was added, no color develops. How should this test be reported?

Positive for molecular nitrogen and negative for nitrite production

The colonies growing on the blood agar plate, as shown in the upper image, are gray, white, and swarming. Note in the image below, that the colonies growing on XLD agar have black centers with pigmentation that does not extend into the agar. A presumptive identification of Proteus species can be made. Select the biochemical reaction that serves to separate Proteus vulgaris from Proteus mirabilis.

Positive indole

Illustrated in the photographs are smooth, entire, gray-white colonies growing on blood agar that are faintly beta hemolytic (left). Light pink-red pigmented entire, smooth colonies grew on MacConkey agar (right). These isolates were recovered from a skin infection incurred by a 28 year old man after swimming in a lake. The pink-red pigmentation of colonies on MacConkey agar suggest lactose fermentation. Biochemical reactions included Acid/Acid KIA reactions indicating fermentation of glucose. Oxidase was positive. Other positive reactions include indole, DNAse, and esculin. Additional biochemical tests identified this isolate as Aeromonas species. The pink-red colonies growing on MacConkey may suggest one of the Enterobacteriaceae. Which of the following choices will exclude this possibility?

Positive oxidase reaction

Which of the following biochemical reactions is most useful in establishing a definitive identification of Staphylococcus aureus?

Positive tube coagulase test

A PYR reaction is shown in the attached image. Which combination of result interpretation and possible organism identification based on the result is correct?

Positive/Enterococcus sp

All of the following sample types should be accepted for a lower respiratory culture, EXCEPT:

Posterior pharynx swab

What reagent should be used in conjunction with calcofluor white when preparing the fungal slide for interpretation?

Potassium hydroxide (KOH)

A doctor is requesting an acid-fast culture on a stool specimen. How should the tech handle this request?

Prepare a direct smear from the sample and only digest the specimen for culture if the smear is positive

A tech in the laboratory is reading a Gram stain from a cerebrospinal fluid. After searching the entire length of the slide for a few minutes, the tech was unable to location any material (cells or bacteria) on the slide. How should the tech proceed?

Prepare a new slide by using cytocentrifugation

Rothia mucilaginosus is a member of the family Micrococcaceae that has been associated with endocarditis in patients after cardiac catheterization, as well as intravenous drug users. Which test listed below would be most helpful in making a species identification?

Presence of a capsule

All of the following are statements concerning the gram stain. Which of the following is a TRUE statement?

Presumptive evidence is provided.

Observation of colonies producing brick red fluorescence under long-wave ultraviolet light on KVLB agar allows for presumptive identification of which anaerobic bacterial genus?

Prevotella

Illustrated in the photograph is the 4 day slow growth of colonies recovered on an anaerobic culture. Note the small size of the colonies growing on anaerobic blood agar, distinctive for brown-black pigmentation surrounded by a wide zone of beta hemolysis. Gram stain revealed small, gram-negative coccobacilli. Most strains are biochemically inactive, although glucose and lactose fermentation are positive (saccharolytic). A common source would be from an infection of the oral cavity or from an infected human bite wound. From these observations, select from the multiple choices the identification of this isolate.

Prevotella melaninogenica

The saccharolytic anaerobe that produces red fluorescing colonies when illuminated with a Wood's lamp, as shown in this photograph, is:

Prevotella species

The blue color seen in the Simmon's citrate agar slant to the right tube shown in this photograph, indicating a positive reaction, results from:

Production of ammonia from ammonium phosphate

What virulence factor is not inherent to bacterium?

Production of opsonins

What is the anatomical feature of a tapeworm that possesses both male and female reproductive structures?

Proglottid

The body of an adult cestode consists of segments called:

Proglottids

What tribe is Morganella morganii in?

Proteeae

A urine sample yielded a lactose-negative, Gram-negative bacillus on primary isolation. Biochemical testing showed the following reactions: Oxidase negative H2S positive Urea positive Phenylalanine deaminase positive The organism which most closely fits this profile belongs to the genus:

Proteus

Shown here is a Kligler Iron Agar (KIA) tube with black pigmentation is confined to the butt of the tube. From the multiple choices, select the bacterial species that produces the reaction seen in the lower image of the KIA tube.

Proteus mirabilis

Shown in this photograph is a Kligler Iron Agar (KIA) slant (left) and a Christensen's urea agar slant (right) after inoculation with an unknown bacterial species and incubation for 24 hours at 35oC. The reactions shown permit a presumptive identification of:

Proteus mirabilis

The attached photograph shows a Christiansen's Urea slant four hours after it was inoculated with a Gram-negative rod. Which of the following organisms is the most likely?

Proteus mirabilis

The bacteria producing the swarming on the surface of the 5% sheep blood agar plate shown in the photograph was indole negative. The most likely identification is:

Proteus mirabilis

The organism growing on Blood Agar and MacConkey Agar in the attached photograph was recovered from the burn wound of a patient. The Gram stain is also attached. This organism is a non-fermenter and can grow at increased temperatures (42 °C). Upon additional testing, the organism was positive for pyocyanin production. Which of the following is the most likely presumptive identification of this organism?

Pseudomonas aeruginosa

The tubes shown in the image are O/F basal medium with glucose and a pH indicator of bromthymol blue. As shown, the tube on the left has a large layer of mineral oil on top of the medium (closed), while the tube on the right does not have a mineral oil overlay (open). The image below demonstrates a typical reaction for which organism?

Pseudomonas aeruginosa

What bacterial species is rarely part of normal microbiota of healthy humans?

Pseudomonas aeruginosa

Which Pseudomonas species produces pyocyanin (bright bluish pigment on Mueller-Hinton agar)?

Pseudomonas aeruginosa

Which of the following is a nonfermenter?

Pseudomonas aeruginosa

Which of the following is oxidase positive?

Pseudomonas aeruginosa

Which Pseudomonas species will have yellow colony pigmentation on blood agar?

Pseudomonas fulva

On sheep blood agar, Haemophilus influenzae may exhibit satellitism around all of the following bacteria, EXCEPT:

Pseudomonas spp.

Nitrate reduction is the process by which nitrate is reduced to nitrite; in denitrification, nitrate is completely reduced to nitrogen gas. Which of the following species denitrifies nitrate?

Pseudomonas stutzeri

The granular, wrinkled, yellow-pigmented colonies shown in the upper photograph were recovered on chocolate agar after 48 hours of incubation from a respiratory specimen collected from a patient with cystic fibrosis. Note in the lower composite photograph that colonies on the surface of blood agar are flat, granular, and only slightly wrinkled. On MacConkey agar the colonies lack lactose fermentation and lack pyocyanin production. The spot oxidase test is positive, and nitrates are reduced. With these observations, select the presumptive identification of this isolate.

Pseudomonas stutzeri

A 31-year-old female with a known history of amebiasis, presented to her physician complaining of bloody diarrhea and fever. Previous patient history revealed that she lives in substandard conditions. Parasitic examination of the woman's stool revealed this suspicious form that measures 20 µm. The identification of this form is:

Pseudoparasite

A 45-year-old mother of two went to her physician because her children were recently diagnosed with ascariasis and she was concerned that she had also contracted the disease. Other than complaining of recent sporadic diarrhea, she was in overall good health. The doctor ordered a stool for ova & parasite examination. This suspicious form, measuring 55 µm was seen throughout the sample. This form is most likely:

Pseudoparasite

This suspicious form, shown here under both low and high power, was found in a stool sample and measures 50 µm.

Pseudoparasite

The fungal organism in the illustration is identified as Sporothrix schenckii and is described as having a delicate 'flowerette' appearance with single-celled conidia borne in a cluster. Each conidium is connected to the tip of single conidiophore by a delicate, thread-like denticle. The mechanism of transmission for this organism is:

Puncture or abrasion

A CSF specimen was sent to the laboratory for analysis. A glucose, protein, and cell count were performed. Based on the following results, what would be the probable cause? AnalyteResultGlucose15 mg/dLProtein150 mg/dLLeukocytes1,000 cells/mm3 neutrophils

Purulent infection

A female was seen by her physician with symptoms of fever, flank pain, frequency, urgency, and dysuria. A urinalysis was performed and had the following results. Which of the following clinical manifestations will this patient have? pH7.6ProteinPositiveBloodPositiveNitritePositiveLeukocyte esterasePositiveBacteriaGram Negative Rods 4+CastsWhite Cell castRed Cell castCulture100,000 cfu/mL of Escherichia coli

Pyelonephritis

The pigment produced on the King's medium agar plate illustrated in this photograph is:

Pyocyanin

Abiotrophia defectiva (formerly Streptococcus defectivus) and Granulicatella adiacens (formerly S. adjacens, then A. adiacens) are the names currently given to two species of what were previously called nutritionally variant streptococci (NVS). What supplement must be added to blood culture medium to recover these organisms in cases of "culture negative endocarditis?"

Pyridoxyl

A 62-year-old female undergoing chemotherapy for breast cancer developed fever, abdominal pain, and foul-smelling diarrhea after receiving clindamycin for 5 days. The photomicrograph is an H & E-stained section of colon biopsy revealing focal ulceration and pseudomembranous inflammation. Each of the following laboratory findings will confirm the presumptive diagnosis of Clostridium difficile-associated colitis EXCEPT:

Recovery of C. difficile in the stool

The disappearance of HBsAg and HBeAg, the persistence of Total anti-HBc, the appearance of anti-HBs, and often the presence of anti-HBe indicates what type of Hepatitis infection?

Recovery phase of HBV infection

To screen for Vancomyin-Resistant Enterococci, which of the following culture sites is most appropriate?

Rectal

A tech receives a request for VRE colonization testing on a patient in the hospital. Which of the following is an appropriate area of the body for culture for screening?

Rectal area

A tech working in the laboratory and receives a call from the floor. The nurse needs to perform a VRE screen on the patient and needs to know what type of specimen to collect. Which of the following is an appropriate specimen for VRE screening?

Rectal swab

What color would the agar be around a colony of Staphylococcus epidermidis growing on mannitol salt agar (MSA)?

Red

Which of the following is a key benefit that molecular methods can offer over culture methods?

Reduced turnaround time

Which of the following two media are appropriate for Bordetella pertussis isolation?

Regan-Lowe charcoal agar and Bordet Gengou media

A sputum specimen for culture is processed in the laboratory. Upon reviewing the Gram stain, the tech finds there are about 15 epithelial cells per low power field and a mix of bacterial flora present. What should the tech do next?

Reject specimen

While working in the laboratory, the tech receives a specimen for culture that has leaked into the transport bag. What should the tech do?

Reject the specimen and contact the physician to recollect the specimen

The formula for oxidative/fermentative (OF) culture media, for the determination of glucose oxidizers, differs from carbohydrate fermentation media by each of the following properties except:

Relative increase in the salt concentration

This Xylose Lysine Decarboxylase (XLD) medium shown in this photograph was isolated from a stool specimen of an immunocompetent adult. Your best action would be to:

Report it as no Salmonella or Shigella isolated

A protected brush specimen was received into the microbiology laboratory from an ICU patient and cultured using a 0.001-mL loop. The culture grew 3 colonies of Pseudomonas aeruginosa. Which of the following is the correct way to report out the organism?

Report out 3,000 CFU/mL of Pseudomonas aeruginosa

On a plate growing Streptococcus pneumoniae, the zone of inhibition around the disk shown in the image has been measured at 23 mm. Based on this result, you should:

Report oxacillin-susceptible

Examine the following test results and identify what action you would take. CAMP: Arrowhead appearance Bacitracin disk: 6mm zone of inhibition PYR: Negative Bile Esculin: Tan appearance, no darkening

Report the isolate as Streptococcus agalactiae

Gram positive cocci isolated from a catheterized urine culture on a 76-year-old male gave the following reactions: Blood agar- creamy, white, opaque colonies with are not hemolytic Catalase- positive Slide coagulase- negative Tube coagulase- negative Novobiocin- susceptible The next action that the medical laboratory professional should take is to:

Report the isolate as coagulase negative staphylococcus

This Gram-positive coccus is catalase positive. The tests shown are a tube coagulase test inoculated with the isolate, and a MRSA screen plate containing 4% NaCl and 6 µg/mL of oxacillin. A 0.5 McFarland standardized inoculum of the isolate is inoculated to the plate. What step should you take next?

Report the isolate as methicillin resistant Staphylococcus aureus.

An alpha hemolytic slightly concave isolate from a respiratory specimen gave a zone of inhibition of 18 mm around the optochin disk. What should the next step be?

Report this organism as Streptococcus pneumoniae.

Schistosoma species can be differentiated by the shape and location of a spine located on the egg. Of the following, which species is paired with the correct location of the spine for that species?

S. mansoni - Large lateral spine

Which of the following Streptococcus spp. exhibits a positive bile solubility test?

S. pneumoniae

Smooth gray-white, convex, glistening non-hemolytic colonies were observed growing on the surface of anaerobic blood agar after 48 hours. This isolate was obtained from a nasal swab specimen. Short Gram positive bacilli in short chains and in diphtheroidal-like clusters were observed on Gram stain. Spot test results included a positive catalase and a negative indole reaction. This organism was presumptively identified as Cutibacterium (Propionibacterium) acnes. With this presumptive identification, select from the multiple choices what the next step should be.

Report with added comment: "probable contaminant"

Edwardsiella tarda is known to be associated with which of the following animals?

Reptiles

Gram stain of a spinal fluid revealed pleomorphic, gram-negative rods. Colonies that appeared on chocolate agar after 24 hours of incubation were gray, opaque, and medium in size. A musty odor was noted when the plate was opened. Gram stain of the colonies on chocolate agar showed small, gram-negative coccobacilli. No growth was seen on sheep blood or MacConkey agar. The next step taken by the technologist to identify this isolate would be to show that the organism:

Requires X and V factors

Parasitized animals that may serve as a source of infection for humans are called:

Reservoir hosts

Which infection control measure above and beyond standard precautions (special precaution) should be used by a healthcare worker who will be collecting a blood specimen from a TB patient?

Respiratory protection controls

Which virus is the MOST common etiological agent of viral respiratory diseases in infants and children?

Respiratory syncytial virus

The amplification of an RNA target through Reverse transcription PCR (RT-PCR) to detect HIV requires the following enzyme for the initial synthesis of DNA from the viral RNA template:

Reverse transcriptase

Which laboratory method is recommended for confirmation of an Influenza A H1N1 subtype infection?

Reverse transcriptase-polymerase chain reaction (RT-PCR)

In the hookworm life cycle, which of the following is considered the noninfective larval form?:

Rhabditiform

The photomicrograph on the right illustrates single conidia in succession both laterally and around the tip of a straight phialide. This type of sporulation, characteristic of certain species of dematiaceous mold, is called:

Rhinocladiella

The type of sporulation of the dematiaceous mold that is illustrated in this photomicrograph is called:

Rhinocladiella

Observed in the image is the microscopic appearance of a sporulation representative of one of the dematiaceous fungi causing chromomycosis. Note that spherical conidia are being produced laterally from the sides of a conidiophore. Which of the following choices represents the type of sporulation illustrated in this image?

Rhinocladiella sporulation

Common colds are most often associated with which agent?

Rhinovirus

Among the non-fermenters, which of the following is the only bacterial species to produce hydrolyze esculin?

Rhizobium radiobacter

Which genera does not belong to the dermatophytes?

Rhizopus

The colony shown in the upper image was recovered from the nasal exudate of a 28-year-old construction worker with sinusitis. The colony grew in 3 days on SabHI agar (combination of Sabouraud dextrose and BHI agar) incubated at 30o C. Note the border-to-border extension of the surface mycelium. As the colony is not species-specific, the identification of this isolate can be made by observing the lower, lactophenol blue-stained image. From these observations, select the identification of this isolate.

Rhizopus species

The hemotoxylin and eosin (H & E) stained tissue reaction in the top photomicrograph reveals a chronic inflammatory reaction with irregular sized, non-septate fungal hyphae, suggestive of one of the Zygomycetes. In practice, a sample of the tissue specimen would be sent to the mycology laboratory to substantiate the diagnosis. What is the illustrated fungal species, recovered from the specimen, seen in the bottom, microscopic photomicrograph?

Rhizopus species

A suspected nocardioform bacterial species was recovered from sputum. The isolate produced mucoid colonies with pink pigment after 4 days on SBA, as shown in the associated image. Staining demonstrated diphtheroid, Gram positive rods with a few branching filaments. It also stained partially acid fast. The most likely identification is:

Rhodococcus equi

The light pink-yellow, mucoid, non-hemolytic colonies on blood agar, an uncommon isolate, belongs to the aerobic actinomycetes. This species is widely spread among farm animals and may cause human respiratory infections upon animal contact. The Gram stain reveals Gram positive cocci, with younger colonies also showing branching bacilli, with residuals seen here. Carbohydrates were not utilized (asaccharolytic), and the decarboxylase reactions are also negative. The presumptive identification is:

Rhodococcus equi

Illustrated in the photograph of the blood agar plate are slow-growing colonies after 72 hours incubation that are pink-white, appear dry, and heaped in areas of confluent growth (arrows). They were recovered from a tooth abscess of a 14-year-old boy. Gram stain reveals short gram positive bacilli that characteristically are in a diphtheroidal arrangement. Key characteristics to provide a definitive identification include positive reactions for catalase, nitrate reduction, esculin, and pyrazinamidase. Based on these observations, select the presumptive identification of this isolate.

Rothia dentocariosa

The 12 µm in diameter cyst illustrated in the lactophenol-stained mount observed in the photomicrograph can be identified as Entamoeba histolytica. Based on the characteristics seen in the image, what feature of the chromatoid bar prompts this differential identification?

Rounded ends

Which condition is associated with this stool parasite with large, broadly oval and bile stained eggs (see photomicrograph)?

Roundworm infection

All of the following organisms are known to be resistant to vancomycin EXCEPT?

Rhodococcus equii

Pink-pigmented, smooth, 48 hour yeast colonies growing on Sabouraud's dextrose have a characteristic appearance leading to a presumptive identification. This environmental yeast may be recovered from cultures obtained from shower curtains, bathtubs, and tooth brushes. The isolate presented here was recovered from peritoneal fluid of a 45 year old woman receiving peritoneal dialysis. Illustrated in the bottom photomicrograph is growth on cornmeal agar revealing loose clusters of yeast cells with the absence of pseudohyphae. Select the identification of this yeast.

Rhodotorula mucilaginosa

The pink-red, yeast-like colonies shown in the photograph together with the production of budding yeast cells singly and in loose clusters in the absence of hyphal formation is characteristic of which of the yeast listed below? (In the past, recovery in laboratory culture this organism was considered a contaminant; however, more recently it has been listed as an "emerging" agent of infection and cannot be considered as insignificant.)

Rhodotorula mucilaginosa

Which yeast species is most likely the colony morphology as seen in the bottom right image

Rhodotorula species

What is the MOST likely identification of a pink yeast isolate, recovered from respiratory secretions of a patient with AIDS, that gave the following results? Germ tube - negativeUrease - positiveBlastospores - positiveArthrospores - negative

Rhodotorula spp.

Rocky Mountain spotted fever (RMSF) is transmitted by the bite of a tick infected with:

Rickettsia rickettsii

A tech receives a call from the floor regarding antimicrobial therapy. The patient culture yielded an aerobic Gram-positive coccus and the physician would like to use an antibiotic that inhibits RNA synthesis. Which of the following antibiotics would be the best choice?

Rifampin

The two most commonly used antibiotics for therapy against uncomplicated tuberculosis are:

Rifampin and Isoniazid

The illustration demonstrates the following stage of the Plasmodium species:

Ring form

Which physician is known for their discovery of Bacillus anthracis and Mycobacterium tuberculosis?

Robert Koch

Each of the following statements regarding Rickettsiaceae are correct EXCEPT:

Rocky mountain spotted fever is almost always geographically restricted to the Rocky mountain region.

A vascular catheter tip is received in the laboratory for aerobic culture. How should the tech proceed in processing this specimen for culture?

Roll the catheter tip across the surface of the agar 4 times

The ideal stool sample for parasitic examination is one that is freshly collected and submitted to the laboratory at:

Room temperature (approximately 22° C)

All of the following specimen collection methods should be used if urine cultures are also required, EXCEPT?

Routinely voided

A coagulase test should be performed to differentiate between which of the following?

S.aureus and coagulase negative staphylococci

The illustrated organism is the anamorph stage of Pseudoallescheria boydii that may cause pulmonary fungus ball infection, mycetomas, endocarditis, and other disseminated infections.

Scedosporium species

Adult forms of the following worms are all hermaphroditic, EXCEPT:

Schistosoma

Illustrated in the upper image is a cercaria that is capable of penetrating the skin of a human who might be swimming in contaminated water. These cercaria in turn enter the circulation, and mature in the portal vascular system where they develop into adult flukes. Distinctively the female flukes occupy the gynecophoral canal of the male fluke, as illustrated in the lower image. From the list of trematode genera, select the genus that represents the parts of the life cycle as described.

Schistosoma

The ovum as illustrated in the high-power photomicrograph, averages 140 µm. These ova are most commonly observed in a urine sediment from a patient complaining of frequent urination, dysuria, hematuria and recurrent urinary tract infections. Note the characteristic delicate, sharply pointed terminal spine (blue arrow) extruding from the anterior margin of the shell. From the multiple choices listed below, select the presumptive identification of this ovum.

Schistosoma haematobium

This suspicious form, found in urine, measures 120 µm by 50 µm. What is the appropriate identification?

Schistosoma haematobium

This suspicious form, found in urine, measures 120 µm by 50 µm. What is the identification?

Schistosoma haematobium egg

The egg in the image to the right, measuring 80 µm, was observed in the stool specimen of a patient complaining of fever, diarrhea, and weight loss. Low grade eosinophilia of 12% was detected in a peripheral blood count. Based on this information, what is the most likely identification of this trematode species?

Schistosoma japonicum

Which of the following parasites may be contracted by swimming in contaminated water?

Schistosoma japonicum

The egg in the picture is found in a stool sample. It has a lateral spine and measures 75 µm by 55 µm. Which intestinal helminth egg is it?

Schistosoma japonicum egg

A 16-year-old male champion athlete went to his doctor complaining of a persistent cough, fever, bloody diarrhea and overall weakness. Upon questioning the patient, it was learned that he had recently competed in a freshwater swimming competition in the Caribbean. Examination revealed a dermatitis on the patient's right calf. A battery of tests were ordered including a CBC, chemistry profile, and a stool for culture and parasitic examination. The CBC revealed the presence of eosinophilia. The other hematology and chemistry tests were unremarkable. The culture was negative. A suspicious egg form was seen on all parasite preparations made from the stool sample submitted. This form measured 165 µm by 68 µm and had a large lateral spine. (See image to the right) This patient is most likely suffering from an infection with:

Schistosoma mansoni

Illustrated in the high power photomicrograph is a large 140 µm ovum as it would appear in a stool specimen preparation. The adult flukes reside in the portal veins of the large intestine where ova are discharged into the lumen and into the feces. Low grade diarrhea may be experienced. From the multiple choices select the species of fluke related to this ovum.

Schistosoma mansoni

Illustrated in the high power view of an H & E-stained tissue section is a granuloma involving the wall of the large intestine. Based on the observation of a sharp spike projecting from the cyst shell (arrow), what is the identification of this parasitic egg?

Schistosoma mansoni

In the following list, which of the parasites has the MOST complex life cycle?

Schistosoma mansoni

The image on the right depicts a suspicious form recovered in stool. This form measures 120 µm by 63 µm, what is the most likely identification?

Schistosoma mansoni

The intestinal parasite pictured was found in stool and measures 170 µm by 63 µm. What is the most likely organism?

Schistosoma mansoni

Which of the following organisms is considered a Helminth?

Schistosoma mansoni

Which one of the following parasites migrates through the circulation (blood) before maturing in the portal venous system?

Schistosoma mansoni

Shigella serotyping is performed by using a polyvalent somatic (O) antisera. A Shigella species grew from culture and serotyped as Group A. Which of the following Shigella species serotypes as Group A?

Shigella dysenteriae

Shigella serotyping is performed by using a polyvalent somatic (O) antisera. A Shigella species grew from culture and serotyped as Group B. Which of the following Shigella species serotypes as Group B?

Shigella flexneri

Which of the following human parasite spreads its infection through ingestion of raw meat or from oocysts from cat feces?

Toxoplasma gondii

A parasitic egg was found in stool and measured 170 µm by 63 µm (see image to the right). Identify the parasitic egg.

Schistosoma mansoni egg

Which of the following parasites is the causative agent of swamp fever?

Schistosoma mansoni egg

The portion of a tapeworm used for attachment to the host's intestine is called the:

Scolex

Observed in the upper image is a yellow-brown colony growing on Sabouraud's Dextrose agar after 72 hours incubation at 30° C, as recovered from a subcutaneous abscess following a traumatic injury in an immune-compromised host. The microscopic appearance is shown in the lower image, revealing relatively large conidia arranged in long chains. Based on these features, select the fungus genus name from the multiple choices.

Scopulariopsis

The chain of conidia illustrated in this photomicrograph, with the deep-staining truncated bases, are called annelloconidia, and are most characteristic of:

Scopulariopsis brumptii

All of the following fungi are considered to cause major opportunistic infections in humans, EXCEPT?

Scopulariopsis species

Which of the following species of hyaline molds produce conidia in chains?

Scopulariopsis species

An acid-fast bacillus is isolated and produces an orange pigment when grown in either the light or the dark. Which type of organism has most likely been isolated?

Scotochromogen

To ensure quality within the preanalytical phase of laboratory testing, quality assurance activities includes monitoring all of the following preanalytical variables EXCEPT:

Selection of reference materials used for validation purposes.

The ONPG (ortho-nitrophenyl-Beta-D-galactopyranoside) test is used to:

Separate late lactose fermenters from lactose negative bacteria based on the production of beta-galactosidase.

The upper image is a 4 day old colony grown on Sabouraud's Dextrose agar, recovered from a bacterial culture that was considered to be a "contaminant". The lower image is a high power image of a methylene-blue stained mount prepared from the surfaces of the colony. With these observations, select the fungus genus from the multiple choices as listed.

Sepedonium

Which of the following is characterized by hypotension due to systemic infection that does not respond to fluid resuscitation (an attempt to replenish body fluid)?

Septic shock

In the upper bi-plate image are shown colonies growing on MacConkey (left), and on blood agar (right). Relatively large confluent gray white colonies are observed growing on blood agar, while smaller smooth convex colonies with a deep red pigmentation are growing on MacConkey agar. Note that the pigment is confined to the colonies growing on MacConkey agar that does not diffuse into the adjacent agar. In follow-up to making a presumptive identification, observe that the colonies growing on the DNase agar in the lower image (right) show a positive reaction with clearing of the adjacent agar, compared to the growth of a negative control growing in the streak lines to the left. From these observations, select from the multiple choices the presumptive identification of this isolate.

Serratia marcescens

The positive phenylalanine deaminase reaction seen in the left tube (green pigmentation in the slant compared to the negative control on the right) may be produced by each of the following bacterial species EXCEPT:

Serratia marcescens

All of the following Enterobacteriaceae below are appropriately matched with the characteristic listed, EXCEPT:

Serratia marscens - Voges-Proskauer negative

All of the following bacterial species produces a yellow pigmented colony when growing on 5% sheep blood agar EXCEPT:

Serratia rubidaea

A sorbitol fermenting organism from a stool specimen is growing on MacConkey with sorbitol agar. The tech decides to double check for E.coli O157:H7 and a serological testing is performed. The serological testing used to identify the somatic antigen (O157) is positive for agglutination. Quality control also passed. What should the tech do next?

Set up biochemical or other testing to identify the organism

A patient is showing signs of an intravenous catheter associated infection. The physician has removed the catheter and sent the catheter tip along with a skin swab of the catheter site to the laboratory for testing. The physician ordered a Gram stain of the skin entry site and a culture of the catheter tip. On which of the following media should the catheter tip be plated?

Sheep Blood Agar and Thioglycollate Broth

All of following are considered normal flora of the gastrointestinal tract EXCEPT:

Shigella

Shigella serotyping is performed by using a polyvalent somatic (O) antisera. A Shigella species grew from culture and serotyped as Group C. Which of the following Shigella species serotypes as Group C?

Shigella boydii

If a TSI agar slant shows a neutral or slightly alkaline slant, acid butt, no/gas production, and no H2S production, the organism might be:

Shigella dysenteriae

Adult Ascaris lumbricoides worms reside in the:

Small intestines

The first intermediate host in all of the fluke life cycles are the:

Snails

The risk of exposure of a person to an infection of tuberculosis (TB) disease may be related to which of the following:

Socially disadvantaged

In order to prepare the acridine orange (AO) reagent, what is added to the AO powder?

Sodium acetate buffer

The dermatophytic fungus shown in this photomicrograph, is recovered from a ringworm lesion of the skin of the back of the hand of an 8-year-old boy. What was the most likely source for this fungus?

Soil in the back yard

A tech is using the H (flagellar) antigen to serotype a suspected Salmonella species. The results of the serotyping are agglutination with one well that indicates a group of possible serotypes, not one particular serotype. Quality control passed. Why did this occur?

Some Salmonella H antigens can occur in multiple strains and serotypes

Which of the following is the ideal method for processing wound swab specimens for a Gram stain and culture?

Specimen should be collected on a single swab that will be placed in 1.0 mL of saline and vortexed. The saline solution should then be used to inoculate all media and prepare the smear.

To identify all the species within the Mycobacterium tuberculosis (MTB) complex, the Amplified Mycobacterium Tuberculosis Direct (MTD) test can be used. The MTD test utilizes both Transcription-Mediated Amplification (TMA) and the Hybridization Protection Assay (HPA). However, before performing these tests, only certain specimen sources can be used. All of the following specimens can be used EXCEPT?

Spinal fluid

Please see the image. Which illustration corresponds with the classification of bacteria seen in section A?

Spiral (spirochetes)

In cases where separate fungal cultures are incubated at both 30° C and 35°-37° C, a dimorphic yeast form may develop within 3-4 days as illustrated in the top photograph. The isolate is commonly recovered from puncture wounds of the fingers, wrists or arms among rose gardeners. The yeast colony has a smooth outer white border surrounding an inner pigmented center of growth that appear to be hyphal strands. What is the yeast identified by observing the microscopic features as illustrated in the bottom lactophenol stained mount?

Sporothrix schenckii

Often recovered from puncture wounds of the fingers, wrists and arms, illustrated in the top photograph is the 4 day growth on SABHI agar after incubation at 30o C. The colony is circumscribed, yellow, rough and wrinkled centrally, surrounded by narrow smooth, white circular growth with a distinct brown-black outer border. The identification can be made by observing the lactophenol blue stained fruiting heads in the bottom photomicrograph. From these observations, select the name of this fungal isolate.

Sporothrix schenckii

The dimorphic fungi that may produce black, yeast-like colonies after prolonged incubation at 37°C is:

Sporothrix schenckii

The ovoid microconidia arranged in a daisy-head pattern at the tip of a straight conidiophore, observed in the photomicrograph on the right, is characteristic of which of the following dimorphic molds?

Sporothrix schenckii

The colonies shown in the upper image, obtained from a biopsy of an ulcerating skin lesion of the arm, are growing on agar slants of Sabouraud's dextrose agar. The lower image is a photomicrograph of a lactophenol blue mount made from a portion of the colony growing in the left slant. The diagnosis is:

Sporotrichosis

The class of protozoa with no apparent organelles for locomotion is known as:

Sporozoa

Which of the following urine specimens is a method of collection for uncontaminated urine from the bladder in uncooperative patients or patients unable to void due to physiologic conditions?

Straight Catheterized Urine

In a HPV infection, where does the viral DNA replicate?

Squamous epithelial cells

What is the most common agent of infection in CSF shunts?

Stahpylococcus sp.

A tech is reviewing a Gram stain from a positive blood culture bottle. The background on the stain shows pink debris and the tech thinks that there is also Gram negative bacilli but is having difficulty differentiating the artifact and possible organisms. What could the tech do next to help determine if bacteria are present in the blood culture bottle?

Stain with Acridine Orange

The McFarland Comparison Card shown in the illustration is used to:

Standardize concentrations of organisms

The image to the right is a gram stain of a positive blood culture. The bacterial genus most likely to grow out in culture is:

Staphylococcus

An infective agent of skin wound infections and an agent of toxic shock syndrome, the large, entire, golden-yellow, smooth convex colonies on blood agar were recovered from a swab specimen after 48 hours incubation at 37o C. In the image to the right, clusters of gram-positive cocci were observed microscopically in a gram stain prepared from one of the colonies. The coagulase reaction was positive. With these observations, select the name of this isolate from the choices given.

Staphylococcus aureus

An infective agent of skin wound infections and an agent of toxic shock syndrome, the large, entire, golden-yellow, smooth convex colonies on blood agar were recovered from a swab specimen after 48 hours incubation at 37° C. In the photomicrograph, clusters of Gram positive cocci were observed microscopically in a Gram stain prepared from one of the colonies. The coagulase reactions are pictured in the lower images. With these observations, select the name of this isolate.

Staphylococcus aureus

Purulent material is obtained from a carbuncle and submitted for bacterial culture. Many Gram positive cocci and white blood cells were seen on direct smear (top right image). Colonies on blood agar are, smooth and gold/yellow surrounded by a narrow zone of beta hemolysis (top left image). Coagulase tests are shown in the bottom images. The slide coagulase test is negative, but the tube coagulase test is positive. The probable presumptive identification is:

Staphylococcus aureus

The slide coagulase test is a rapid method for identifying which of the following organisms?

Staphylococcus aureus

Which of the following Staphylococcus species will produce yellow colonies on mannitol salt agar?

Staphylococcus aureus

Which of the following gastrointestinal pathogens has an incubation period of 1-8 hours?

Staphylococcus aureus

Which of the following organisms is both a transient colonizer of skin, as well as the most common cause of bacterial skin infections?

Staphylococcus aureus

Which of these organisms is associated with the condition known as toxic shock syndrome?

Staphylococcus aureus

A Staphylococcus species recovered from a CSF shunt culture was found to produce acid from sucrose and maltose and showed alkaline phosphatase activity. The Staphylococcus was also coagulase negative. The most likely identification is:

Staphylococcus epidermidis

A Staphylococcus species recovered from a blood culture was found to produce acid from sucrose and maltose and showed alkaline phosphatase activity. The Staphylococcus was also coagulase negative. The same organism was also found in a culture from the central line tip. The most likely identification is:

Staphylococcus epidermidis

A body fluid was sent to the microbiology laboratory for culture and after 48 hours of non-CO2 incubation, a small catalase positive, coagulase negative, Gram positive cocci in clusters grew on sheep blood agar. This organism was considered to be a possible contaminate, since this organism is part of the normal skin microbiota. Which of the following organisms grew in the body fluid?

Staphylococcus epidermidis

A left arm abscess collected from an 8-year-old male patient grew small white colonies on 5% sheep blood agar after 24 hours incubation at 35°C in 5-10% CO2. The Gram stain of the organism showed small tightly grouped Gram positive cocci. Which of the following organisms is the most likely identification?

Staphylococcus epidermidis

Each of the bacterial species listed below may be associated with culture-negative endocarditis EXCEPT:

Staphylococcus epidermidis

Which organism is associated with sinusitis and otitis and is also considered a leading cause of meningitis with or without bacteremia?

Streptococcus pneumoniae

Observed on the surface of blood agar are smooth, white, 48-hour-old colonies incubated at 37oC, demonstrating a positive catalase reaction and a negative coagulase reaction. The sample was taken from an intravenous catheter. In the photomicrograph are gram positive cocci distinctly arranged in loose clusters and in tetrad formation. From these observations, select the presumptive identification of this isolate.

Staphylococcus epidermidis

Out of the given choices below, which one of the following bacteria is the MOST frequent cause of prosthetic heart valve infections occurring after heart surgery?

Staphylococcus epidermidis

Which of the following is the most common etiologic agent identified in prosthetic valve endocarditis?

Staphylococcus epidermidis

The photograph illustrates a positive tube coagulase test (Tube A) as compared to the fluid, uncoagulated appearance of the negative control (Tube B). Each of the following Staphylococcus species may produce the reaction seen in Tube A except:

Staphylococcus lugdunensis

All of the following organisms have capsular material as a defense mechanism EXCEPT:

Staphylococcus saprophyticus

Based on the results below, what is the most likely organism? Gram stain: Positive cocci Catalase: Positive Coagulase: Negative Bacitracin susceptibility: Resistant Novobiocin susceptibility: Resistant

Staphylococcus saprophyticus

Illustrated in the photograph are smooth, non-hemolytic, white 48 hour old colonies incubated at 37oC growing on the surface of blood agar. This isolate was recovered from a urine culture. Microscopic examination of a gram stain reveals gram positive cocci. The catalase reaction was positive and the coagulase test was negative. This isolate is a common agent of urinary tract infections. What is the name of this isolate?

Staphylococcus saprophyticus

This is a catalase-positive, coagulase-negative, gram-positive coccus isolated from a urine specimen from a 20-year-old female college student. The image shown is a Mueller Hinton plate streaked with a 0.5 MacFarland standardized inoculum and a 5 microgram disk of novobiocin after overnight incubation. What is the identification of the isolate?

Staphylococcus saprophyticus

Illustrated in the top photograph is the 3 day growth of a colony on Sabouraud's dextrose (SAB) agar incubated at 35oC. The colony surface is cottony with distinct radial striations. The reverse of the colony shows dark brown to black pigmentation. The bottom photomicrograph illustrates the distinctive conidial formation. With these observations, select the correct identification of this fungus.

Stemphylium species

The entire, smooth, golden yellow-pigmented non-hemolytic colonies on the surface of the blood agar plate seen in the upper image have been recovered in hospital acquired infections from patients with cystic fibrosis. A Gram stain prepared from one of the colonies as shown in the lower image, reveal long, narrow gram-negative bacilli arranged singly. Polar flagella would be seen in flagellar stains. All carbohydrate reactions are negative except for the oxidative utilization of glucose and maltose and the organism tested negative for oxidase. Positive biochemical reaction for lysine assists in making a definitive identification. Based on these observations, select the identification of this isolate.

Stenotrophomonas maltophilia

The observation of darkly pigmented colonies on agar as illustrated in this photograph is somewhat of a surprise. The colonies of each of the following bacterial species may have an appearance similar to that seen here, EXCEPT:

Stenotrophomonas maltophilia

A mixture of Gram positive and Gram negative bacteria may be present within the same field of a slide of all of the following EXCEPT:

Sterile cerebrospinal fluid

The specimen of choice for the recovery of Entamoeba hartmanni is:

Stool

Which of the following specimen types is suitable for the recovery of Entamoeba histolytica?

Stool

A 30-year-old laboratory worker in New York, doing extensive research on laboratory mice, developed sudden onset of fever, chills, headache and muscle aches. He remembered being bitten by one of the mice about a week previously, although the skin wound healed without incidence. A direct gram stain from the laboratory worker is shown and includes the microrganism causing disease.

Streptobacillus moniliformis

Which of the following species are Gram-positive?

Streptococcus

Each of the following bacterial species work synergistically to produce bacterial vaginitis EXCEPT:

Streptococcus agalactiae

Hippurate hydrolysis is an important characteristic in the definitive laboratory identification of the beta-hemolytic streptococci. The positive ninhydrin reaction, seen in the left tube in the photograph, is produced by:

Streptococcus agalactiae

The entire, smooth, transparent colonies surrounded by distinct zones of beta hemolysis, as illustrated in the photograph to the upper left, were recovered after 24 hours incubation from a vaginal canal swab culture from a 26-year-old mother with signs of premature labor during her 35th week of gestation. Observed in a Gram stain prepared from one of the colonies were Gram positive cocci that were arranged in chains of 4 to 15 cells (upper right). More characteristic is the arrow-head zone of beta hemolysis observed in the agar CAMP test shown in the lower right image. From these observations, the presumptive identification of this isolate is most likely?

Streptococcus agalactiae

The detection of a distinct odor is often helpful in the presumptive identification of bacterial culture isolates. Which bacterial species may produce a distinctive odor of butterscotch or honeysuckle?

Streptococcus anginosus

Illustrated in the top photograph are colonies on blood agar after 48-hour growth at 37° C incubation. The colonies are non-hemolytic, small, entire, smooth, and gray-white. Small Gram positive cocci arranged in short chains are seen on Gram stain as illustrated in the lower photomicrograph. Key to the identification is the rapid production of esculin and do not grow in 6.5% NaCl broth. What is the identification of this organism?

Streptococcus equinus

A 67-year-old man was seen in the emergency room complaining of cough, fever, and piercing right posterior chest pain. X-ray of the chest revealed consolidation of the right middle lobe of the lung. A sputum culture grew the bacterial species shown in the upper photograph. The lower photomicrograph illustrates a gram-stain of the sputum specimen. The most likely cause of the pneumonia is:

Streptococcus pneumoniae

A catalase-negative, a-hemolytic, gram-positive diplococci was isolated from a sputum specimen. The image shown here demonstrates a zone of growth inhibition around the "P disk," indicating optochin susceptibility. What is the identification of this isolate?

Streptococcus pneumoniae

A patient was admitted to the hospital recently with an obvious infection. A sputum specimen was submitted and the microbiologist inoculated it to sheep's blood agar. Based on the colony morphology and the alpha hemolysis seen in the image to the right, the most likely identification is:

Streptococcus pneumoniae

A presumptive identification of a bacterial species can often be made by observing the type of hemolysis when grown on 5% sheep blood agar. Which of the following organisms is nearly always alpha hemolytic?

Streptococcus pneumoniae

Examine the gram stain illustration. The organism labeled "A" is most likely which of the following?

Streptococcus pneumoniae

Small, gray, alpha hemolytic colonies with indented centers were isolated on sheep blood agar from a peritoneal fluid. The following biochemicals were performed: Gram Stain: Gram positive lancet-shaped cocci in chains and pairs Catalase: Negative Optochin susceptibility: Sensitive >14 mmIdentify the organism from the choices provided.

Streptococcus pneumoniae

The microscopic image shown here is a direct Gram stain of sputum obtained from a 70-year-old man complaining of cough, sputum production, and chest pain. This organism was alpha-hemolytic on blood agar, catalase negative, optochin ("P disk") susceptible, and bile soluble. What is the identity of this organism?

Streptococcus pneumoniae

The microscopic view of a Gram stained sputum specimen reveals lancet-shaped, Gram positive diplococci. What presumptive identification may be made?

Streptococcus pneumoniae

The most frequent cause of bacterial meningitis in adults and in children is:

Streptococcus pneumoniae

The optochin (ethylhydrocupreine hydrochloride) disk is most often used for the identification of which organism?

Streptococcus pneumoniae

The organism in the attached photos was isolated from a sputum specimen. The blood agar plates were incubated at 37° C. The upper photo shows 24 hour incubation and the lower photo shows 48 hour incubation. The Gram stain showed lancet-shaped Gram positive cocci in pairs. What is the most likely identification of this organism?

Streptococcus pneumoniae

This isolate is a catalase negative, gram positive coccus on sheep blood agar. The P disk has 5µg of optochin and the zone around it is 16 mm. It has been streaked perpendicular to a beta-lysin producting strain of Staphylococcus aureus. The presumptive identification is:

Streptococcus pneumoniae

Which of the following organisms is the leading cause of bacterial meningitis in infants, young children, and adults in the United States?

Streptococcus pneumoniae

Which of the following organisms typically produces umbilicate (depressed center, concave) colonies?

Streptococcus pneumoniae

Which of the following parasites can cross the placenta and cause serious infection to the fetus?

Toxoplasma gondii

The small, transparent, gray-yellow 48 hour colonies incubated at 37°C. as illustrated in the upper photograph, are surrounded by wide zones of beta hemolysis. This culture was obtained from a throat swab of a patient with pharyngitis. The lower photograph demonstrates susceptibility of this isolate to the bacitracin "A" disc. What is the presumptive identification of this isolate?

Streptococcus pyogenes (Group A)

Illustrated in the top photograph are alpha-hemolytic, entire, gray-white convex colonies that are of a bacterial species that was found to be susceptible to vancomycin. In the lower photomicrograph, gram-positive cocci arranged in chains and in loose clusters that are not species distinctive are seen. Select the bacterial species that are uncommonly vancomycin resistant.

Streptococcus species

Observe the Optochin "P" disc reaction Illustrated in the upper left photograph on the surface of blood agar. Heavy growth of tiny, alpha hemolytic colonies are observed growing on the agar surface that extend to the outer margins of the paper disc. The Gram stain presented in the lower photomicrograph reveals small Gram positive cocci lying singly, in small clusters, and more typically in long chains. This isolate has been recovered from blood cultures in cases of post-valvular endocarditis. Select the presumptive identification of this isolate.

Streptococcus viridans

The photograph on the right is of a 5% sheep blood agar plate inoculated with a throat culture. It is common practice to stab the agar with the inoculating needle, as seen at the tip of the arrow, in order to detect or accentuate the reaction of:

Streptolysin O

The ability of streptococci to spread within the tissues and cause rapidly advancing cellulitis is due to the production of several virulence factors. Each of the following correctly describes the effects of the specific virulence factor EXCEPT:

Streptolysin S is associated with the rash of scarlet fever and the pathogenesis of streptococcal toxic shock like syndrome.

Which bacterial species is most likely represented by the opaque, chalky, white colony appearance as illustrated in the photograph?

Streptomyces anulatus

The colonies growing on Middlebrook agar as shown in the upper left photograph were recovered after 5 days incubation from an aspirate from a superficial skin infection. The gram stain revealed branching bacilli as seen in the lower image. These organisms are acid-fast negative. Illustrated in the upper right photograph are colonies growing on casein medium demonstrating hydrolysis. The MOST likely identification is:

Streptomyces species

The body of a cestode is known as its:

Strobila

Illustrated in this photomicrograph of a lactophenol blue preparation of a urine sediment is a cluster of yeast cells that were presumptively identified as Cryptococcus species. Further characteristics that may assist in confirming this identification are:

Strong phenoloxidase activity

This suspicious form was recovered in stool. What is the identification?

Strongyloides rhabditiform larva

A CSF spinal shunt specimen grew out an Enterococcus species. What parasitic species should be of concern when an Enterococcus species is isolated from a spinal fluid?

Strongyloides stercoralis

A fresh stool sample was submitted to the laboratory for an ova and parasites examination on a 30-year-old male who presented to a local clinic complaining of gastrointestinal discomfort and overall weakness. The sample was immediately processed and this suspicious form was seen. No other suspicious forms were observed. What is the most likely identification of this parasite?

Strongyloides stercoralis

Illustrated in the upper image is the anterior portion of a nematode filariform larva with a short buccal cavity. The ovum illustrated in the lower image is also part of the life cycle of this nematode. With these observations, what presumptive identification can be made from the parasite species listed below?

Strongyloides stercoralis

In cases of suspected intestinal parasitic disease, select the name of the parasite, as illustrated by the 50 µm ovum in this image, that may be detected in upper respiratory secretions when stool specimen preparations are negative.

Strongyloides stercoralis

The rhabditiform larva shown in this image was observed in a mount prepared from a diarrheal stool specimen. This patient also complained of persistent cough and increased shortness of breath. From the list of answer choices below, what presumptive identification can be made?

Strongyloides stercoralis

A stool specimen has been left at room temperature overnight. The next day, many motile larvae with a short buccal cavity are seen upon microscopic exam, but there are no ova observed. What is the most likely identification and life stage of this parasite?

Strongyloides stercoralis - rhabditiform larvae

A tech is testing a sorbitol negative isolate for possible E.coli O157: H7 from the MacConkey with sorbitol agar plate. The biochemical identification proves the organism is E.coli. Serological testing for the O157 somatic antigen is positive. Serological testing for the H7 flagellar antigen is negative. Quality control for all serological testing passed. What should the tech do next?

Subculture the organism to motility medium for repeat H7 serological testing

Adult cestodes utilize which body part to attach to the human intestine?

Suckers

An organism isolated from a sputum specimen and appeared as a dry, wrinkled, off-white colony on sheep blood agar. A Gram stain was performed and Gram positive branching rods were seen. In addition, a modified acid fast was performed and was positive. The organism was later identified as a Norcardia species. Which of the following antibiotics is the appropriate treatment?

Sulfonamides

Due to the similarity of pulmonary and cutaneous clinical manifestations caused by Nocardia species and many other organisms, proper laboratory identification will allow for the proper selection of antimicrobial treatment, since Nocardia species are generally susceptible to:

Sulfonamides

The best sample to obtain in order to diagnosis the parasite causing the posterior scalp nodule as illustrated in the photograph is:

Superficial skin snip

Which parasite can be recovered from the eye?

Toxoplasma gondii

A urine specimen, from a premature infant, was sent for culture to the microbiology laboratory and it grew out 30,000 cfu/mL of a coagulase negative staphylococcus. The physician felt that the growth was skin contamination as the urine was collected in a U-Bag that was attached around the infant's genitalia area. The physician sent a second specimen for culture and it was reported as no growth after 48 hours. Which of the following specimens is the most probable specimen type for the second specimen that was sent to the microbiology laboratory for culture?

Suprapubic Bladder Aspiration Urine

A urine culture contains the following organisms:

Suprapubic aspiration

The tech in microbiology receives a call from the outpatient center where the doctor wants to test a patient's wound to determine if is caused by cutaneous anthrax. What should the tech indicate is a proper specimen for collection to detect cutaneous anthrax?

Swab under edge of skin lesion

The border to border, light tan delicate cottony grown in 3 days on SABHI agar incubated at 30° C as illustrated in the top photograph is characteristic of one of the Zygomycetes. As the colony morphology is non-selective, the identification of this isolate is made by observing the characteristic fruiting head as illustrated in the bottom lactophenol blue stained photomicrograph. From these observations, select the name of this isolate from the list of multiple choices.

Syncephalastrum species

A patient came into the emergency department with a swollen knee and the physician drained 20 mL of fluid from the patient's knee. What is the name of the fluid collected?

Synovial fluid

If septic arthritis is suspected, specimens from which of the following normally sterile sites should be collected to detect the microorganism causing the condition?

Synovial fluid

A combination of nontreponemal testing (VDRL or RPR) and treponemal testing (TP-PA or EIA) is used to confirm:

Syphilis

The VDRL and RPR are used to provide presumptive identification of which infection?

Syphilis

Which cell is targeted by the AIDS virus?

T lymphocyte

A 6-year-old girl was seen in the emergency department with pain and tenderness in her lower right quadrant. A CBC showed a high white blood cell count with increased segmented neutrophils and bands. The child was admitted to surgery with a diagnosis of appendicitis. During surgery the appendix appeared normal, but an enlarged node was removed and cultured. A diagnosis of mesenteric lymphadenitis was made. Gram-negative rods were isolated. Which of the following biochemical results are most likely produced by the suspect organism?

TSIA acid over acid, H2S negative, lysine negative, indole variable, urea positive

A 29-year-old male steak house owner from Arizona presented to his doctor complaining of weight loss, abdominal pain and diarrhea. Patient history revealed that the man eats all of his meals at his restaurant and his favorite meat is rare sirloin steak. The man also noted that he had recently been on anti-parasitic medication. The doctor ordered a stool for parasitic examination. These two suspicious forms were seen. The patient is most likely suffering from an infection with:

Taenia saginata

Illustrated in the photograph is a single proglottid representative of one of the cestode tapeworms. This proglottid is longer than wide and has well over 13 lateral uterine branches. Select the presumptive identification of this tapeworm proglottid.

Taenia saginata

Which of the following statements about hepatitis C virus (HCV) is true?

The majority of individuals who are infected with HCV and develop antibodies in their serum (seroconvert) will develop a chronic infection and active liver disease.

A cyst was found in a human brain biopsy with characteristics of a cysticercus. These cysts may develop also in other body sites, particularly in the lungs. Cysticercosis in humans most commonly occurs as part of the life cycle of a tapeworm, the species of which is indicated by the proglottid shown in this image. From these observations, what is the name of the tapeworm of which cysticercosis is part of its life cycle?

Taenia solium

Based on the morphologic features of this 40 µm (in diameter) ovum, as seen in the upper photomicrograph with the accompanying scolex of the adult worm illustrated in the lower image, select the presumptive identification of this cestode from the multiple choice answers listed below.

Taenia solium

Illustrated in the image is a large cyst of the brain as it would be observed at autopsy. This cystic lesion is characteristic of a Cysticercus. From the list of multiple choices, select the parasite of which this cystic lesion is part of the life cycle.

Taenia solium

Illustrated in this compound Image is a section of brain to the left, within which a small cyst is observed (arrow). The image to the right is a low power microscopic close in view of the cyst, within which is observed a developing embryo, that can be recognized as a cysticercus. Select from the multiple choices the name of the human tapeworm for which a cysticercus cyst serves as an early stage in the development of its life cycle.

Taenia solium

The following parasite is transmitted through the ingestion of contaminated pork:

Taenia solium

The morphologic structures depicted on this scolex from a cestode parasite include: A) rostellum, B) hooklets, and C) suckers. Identify the cestode species associated with this scolex.

Taenia solium

Upon reviewing a fecal preparation for Ova and Parasites, a technologist thought they had just identified the egg of Taenia saginata. After a quick look, the microbiology supervisor reminded the technologist that T. saginata eggs are indistinguishable from which of the following?

Taenia solium

Of the following parasites, which parasitic scolex has a rostellum, hooklets, and 4 suckers?

Taenia solium scolex

What is this parasite that resides in the human intestine?

Taenia solium scolex

What parasite resides in the human intestines and is identified in the picture?

Taenia solium scolex

The ovum, illustrated in this photograph, is in an immature stage of development, and is surrounded by residual yolk sack material and membrane. It measures 50 µm in diameter. What is the presumptive identification of this ovum?

Taenia species

Identify the form found in stool (illustrated here), measuring 33 µm in diameter.

Taenia species egg

This suspicious form was seen in a stool specimen and measures 33 µm by 28 µm. What is the identification of this form?

Taenia species egg

The 40 µm in diameter ovum illustrated in the photograph may be observed in the stool specimens of individuals presenting with minimal abdominal discomfort and low grade diarrhea. Pairs of hooklets are observed internally in the absence of an internal membrane. Select from the multiple choice answers the presumptive identification of this cestode ovum.

Taenia spp.

All of the following would be effective methods to reduce the risk of becoming infected with the H1N1 virus, EXCEPT?

Take an aspirin every day.

Illustrated in the upper image is a 6-day-old colony growing on the surface of Sabouraud Dextrose agar. Note the distinct light green and pink granular colony surrounded with a reddish margin with diffusion of the wine-red pigment into the agar. This type of colony may be recovered from a sputum specimen of a person with travel history to Southeast Asia. The lower image is of a microscopic mount stained with lactophenol blue. From these characteristics, select the identification of this fungal isolate.

Talaromyces (Penicillium) marneffei

Beta-lactam antibiotics interfere with cell wall synthesis by all of the following, EXCEPT:

Targeting the 30S ribosomal subunit

A tech receives a call from the floor regarding antimicrobial therapy. The patient culture yielded an aerobic Gram-negative bacillus and the physician would like to use an antibiotic that inhibits protein translation. Which of the following antibiotics would be the best choice?

Tetracycline

Sulfonamides, such as sulfamethoxazole (SMZ), and trimethoprim (TMP), work by targeting:

Tetrahydrofolate synthesis; preventing bacterial DNA synthesis

Baseline testing for latent Mycobacterium tuberculosis infection (LTBI) is recommended for all newly-hired healthcare workers. In which of these cases would a tuberculin skin test (TST) be repeated a second time, one to three weeks after the first test?

The first test is negative and the new employee has never been tested for LTBI before.

The ability to detect and identify human parasites is directly linked to the following, EXCEPT:

The genus and species of the parasite

All of the following are true concerning clinical specimens that are gram stained before culturing, EXCEPT:

The gram stain eliminates the need for a culture.

Koch's postulates include all of the following EXCEPT for which statement?

The isolated organism, when injected into a human host, will produce the disease.

A tech working in the laboratory receives a phone call from a doctor who is upset that his patient has a negative urine culture. The doctor indicates that the urinalysis result is positive for leukocyte esterase so the culture should be positive. The doctor feels that the urine culture was not properly handled. How can you explain the discrepancy in the urinalysis and culture to the doctor?

The patient could have another infection, such as a sexually transmitted infection (STI)

The likelihood of colonization and/or infection with Clostridium difficile is enhanced by all of the following except:

The patient has been previously treated at an orthopedic sports clinic

A tech is working on a culture and accidentally enters an incorrect organism. The tech quickly issues a corrected report which includes both the incorrect result and the new, correct result. The tech completes the report and moves on to the next patient culture. What part of the corrected report process is missing or incorrect?

The physician was not called to be notified of the corrected report

What is the identifying characteristic of Aureobasidium pullulans?

The production of a black yeast-like colony

What is the most helpful feature in differentiating the Zygomycetes from the other hyaline molds in the clinical mycology laboratory?

The production of spores within sporangia

Two techs performed E.coli O157:H7 serotyping on a suspected colony. The serotyping uses the O157 somatic antigen as the target for agglutination. One tech performed quality control and patient samples by using a suspension of the colony and latex reagent. The results reported by the tech were positive. The second tech also did the serotyping using quality control and patient samples by using a suspension of colony, latex reagent, and the isolate suspension with the negative control. The second tech's results were negative. Quality control passed in all testing. Why did the techs obtained different results for the serotyping?

The second tech tested the suspension with negative control

Which of the following statements is true regarding the Gram-stained smear that is represented by this image?

The smear is underdecolorized and shows precipitated and crystallized stain.

At an outpatient clinic, a patient comes in with an order for stool ova and parasites (O & P). How should this specimen be collected and transported for best test results?

The specimen should be immediately placed in recipients containing polyvinyl alcohol (PVA) or formalin and transported to the laboratory.

A urine culture and sensitivity (C&S) specimen is collected at 8 AM at an outpatient clinic and the courier will not be able to pick it up until 2 PM that same day. If refrigeration is not available, how should the specimen be stored until testing is performed?

The specimen should be placed in a container with the proper preservative.

A vaginal swab for anaerobic culture is received in the laboratory. How should this specimen be handled?

The specimen should be rejected

The most likely primary site of infection represented by the Staphylococcus species growing on the surface of this agar plate with a 2 mm zone of inhibition around a 5 µg novobiocin disk is:

The urinary tract

A stool specimen was received in the laboratory for an O & P examination. The medical laboratory scientist performed a direct wet mount and found suspicious forms. A formalin ethyl acetate concentration procedure was performed and the top layer was examined with no suspicious forms observed. A slide made from the top layer was stained with Trichrome and again no suspicious forms were noted. Which of the following is the most likely explanation for these discrepant results?

The wrong layer was examined following the formalin ethyl acetate concentration procedure.

Examine this photo of a 5% sheep blood agar plate from a wound culture workup. All of the following direct tests would be helpful in making an immediate presumptive identification of the organism growing on the plate EXCEPT:

Thermostable endonuclease

The federal government has categorized critical biological agents into three groups: A, B, and C. Why are the agents in category A classified as the highest-priority?

These organisms can be easily disseminated or transmitted person-to-person.

Organisms such as coagulase-negative Staphylococcus, Corynebacterium, and alpha streptococcus species are all found on the skin and represent normal skin flora. All of the following are functions of normal skin flora EXCEPT?

They aid in the transmission of nosocomial infections

All of the following are true about all members of the Enterobacteriaceae, EXCEPT:

They are all oxidase positive

Brucella suis and Salmonella typhi can commonly infect the spleen, liver, and bone marrow. Which of the following reasons allow these two organisms to cause a systemic infection?

They are both ingested by monocytes and/or macrophages within the spleen, liver, and bone marrow

All of the following statements concerning Rickettsia species are true, EXCEPT:

They are cultured in many hospital laboratories.

Which of the following statements about Gram-positive bacteria is TRUE?

They resist acetone-alcohol decolorization

Methods of detecting and identifying intestinal parasites include all of the following except:

Thin and think Giemsa smear

Which of the following characteristics will produce the most desirable smear to be examined using a Gram stain?

Thin, monolayer of material from an abscess on a slide

Which type of stain is recommended to speciate Plasmodium species?

Thin-stained Giemsa smears

A purulent fluid was collected between the lung and the chest wall. What is the name of this fluid?

Thoracentesis fluid

A thoracentesis specimen was collected and sent to the laboratory for testing. What body area was this specimen collected?

Thorax

Aerobic actinomycetes can cause different types of infections. All of the following are acceptable sites for the recovery of aerobic actinomycetes EXCEPT?

Throat

All of the following choices are acceptable specimens for anaerobic culture, EXCEPT?

Throat swab

All of the following specimens would be considered suitable for anaerobic culture, EXCEPT?

Throat swab

Which of the following arthropods would be classified as Arachnida?

Ticks

All of the following characteristics should be observed for and noted in the macroscopic examination of a stool sample for parasites EXCEPT?

Time that last meal occurred

Which of the following is a characteristic of Francisella tularensis?

Tiny, weak-staining, gram-negative coccobacilli

What specimen type should be gently minced before inoculating fungal media?

Tissue

What is the recommended treatment if the patient is passing both cysts and trophozoites with an Entamoeba histolytica infection?

Tissue amebicide followed by a luminal amebicide

What is the purpose of allowing a prepared KOH mount to sit for 30 minutes?

To dissolve the background keratin and reveal fungal elements.

What is the purpose of a trichrome stain?

To identify protozoan trophozoites and cysts in fecal samples.

When serotyping Salmonella, Shigella, and Escherichia coli 0157:H7, typing should be performed from a non-sugar-containing medium, such as 5% sheep blood agar. The reason for this is which of the following?

To prevent false positive results

Fluoroquinolones, such as ciprofloxacin, work by targeting:

Topoisomerases, inhibiting bacterial DNA replication

The diffuse erythroderma and edema of the hand shown in the upper photograph is of a 24 year old female with fever, headache and hypotension. The blood agar plate shown in the lower photograph was inoculated with purulent material aspirated from a vertebral disk abscess. The most likely condition is:

Toxic shock syndrome

Contact with infected cat feces is responsible for the transmission of:

Toxoplasma gondii

Illustrated in the photomicrograph is a Giemsa-stained impression smear prepared from an aspirate of an enlarged cervical lymph node. Human infections are acquired through the ingestion of poorly cooked meat. Pregnant women in particular are advised to avoid handling of cats and the ingestion of under-cooked meat. Based on the morphology of the 8 µm long tachyzoites observed in the photomicrograph, select the name of the protozoan parasite as listed for making a presumptive identification.

Toxoplasma gondii

Which obligate intracellular parasite may be transmitted to humans though accidental ingestion of infective oocysts from cat feces when gardening or changing a litterbox?

Toxoplasma gondii

The scaling, pink-white appearance of the foot shown in the photograph is characteristic of "Athlete's Foot", a skin infection incurred by athletes after barefoot walks to and from the shower stall. A cottony gray-white fungal colony grew in 5 days from a skin scraping. The identification was made by the microscopic appearance of a mount made from the colony as illustrated in the photomicrograph. From these observations, select the name of the fungal species.

Trichophyton rubrum

Which of the following fungi is the cause of tinea pedis, ringworm of the feet?

Trichophyton rubrum

Illustrated in the top photograph is the picture of a yellow to buff colored colony, suede-like in consistency, recovered from a hairless inflammatory lesion of the skin of the scalp of a young male athlete. The more definitive identification can be made from observation of the lactophenol blue mount illustrated in the bottom photomicrograph, prepared from a small sample of the colony surface mycelium. Based on these observations, select from the multiple choices the presumptive identification.

Trichophyton tonsurans

The upper image to the right depicts a small circular white colony with a downy surface, recovered from a skin scraping specimen after 7 days of growth on agar supplemented with thiamine and inositol. The identification is made by observing the aerial hyphae (middle image) and the underlying chains of pigmented chlamydospores among the hyphae (lower image). Based on this information, what is the most likely identification of this dermatophyte?

Trichophyton verrucosum

The following organism causes White Piedra which infects hairs on the face, scalp, and body areas:

Trichosporon beigelii

A soft, yellow to pale brown nodule is found growing around the hair shaft of an individual from a tropical location. On direct microscopic examination, hyaline hyphae with numerous rectangular arthroconidia were observed. The presence of the arthroconidia aid in differentiating this organism from other yeast. The most likely identification is:

Trichosporon species

A 31-year-old male missionary worker recently returned from Africa where he helped a small rural community update their sanitation practices. He presented to his physician weak and complained of recent weight loss, abdominal pain, and diarrhea that was often bloody. The doctor ordered a battery of tests including a complete blood count (CBC) and stool for parasite examination. The CBC revealed eosinophilia and anemia. This suspicious form was seen on the wet preparations. It measured 52 µm by 27 µm. What parasite is mostly likely present?

Trichuris trichiura

A 4-year-old female from South Carolina who was suffering from malaise, bloody diarrhea and abdominal pain, was rushed to the emergency room. Examination revealed rectal prolapse. Stool was submitted for parasitic examination and this suspicious form was seen. It measures 45 µm by 20 µm. Which of the following is the correct identity of this suspicious form?

Trichuris trichiura

From the following list of parasites, identify which one has the smallest egg?

Trichuris trichiura

Nematodes are round and elongated and typically look like an earthworm. Nematodes can be found in decaying vegetation or moist soil. Of the following organisms listed, which one is considered a nematode?

Trichuris trichiura

The 50 µm ovum illustrated in this image was recovered from a diarrheal stool specimen from a 30-year-old male one month after a visit in Puerto Rico. Dysentery, abdominal discomfort, and low grade diarrhea had been experienced. Select the most likely genus/species identification.

Trichuris trichiura

Whipworm infection may be diagnosed in stool specimens by microscopic observation of adult worms or barrel-shaped eggs with polar plugs. Which species is known as the whipworm?

Trichuris trichiura

The image is:

Trichuris trichiura egg

This parasite was recovered in a veterinary stool sample. Which of the following human parasites does it most closely resemble?

Trichuris trichiura egg

The motile, active feeding stage of the ameba is known as the:

Trophozoite

Which Plasmodium morphologic form is considered most immature?

Trophozoite

An iodine prep is LEAST helpful in the identification of which parasitic stage?

Trophozoites

The motile, feeding stage of the amoebas and flagellates is called:

Trophozoites

A blood specimen collected in EDTA was submitted to the laboratory from a patient that recently returned from a missionary trip to West Africa. The patient presented with fever and lymphadenopathy. The physician requested that the laboratory examine a blood smear for parasitic infection. The image shows the parasite in the specimen. Identify this parasite.

Trypanosoma brucei

Coccidia parasites are often acquired by fecal-oral routes by ingesting contaminated food or water. All of the following are coccidia parasites EXCEPT?

Trypanosoma cruzi

Illustrated in the close-in photomicrograph of a stained blood smear is a circulating trypomastigote measuring 20 µm. The disease represented by this peripheral blood smear most commonly occurs in South and Latin America, often affecting children. Human infection is transmitted via an arthropod vector, the reduviid bug, resulting in an inflamed ulcer of the skin called a chagoma. Chronic infections in the form of tissue granulomas may disseminate to distant organs, often to the muscle of the heart. With this background, select the name of the protozoan flagellate causing this disease.

Trypanosoma cruzi

The image shown here is a thin blood smear stained with Giemsa. Identify the parasitic organism present in the blood smear, which is transmitted by the triatomid bug, or "kissing bug." (Image is courtesy of the CDC.)

Trypanosoma cruzi

Xenodiagnosis has historically been used to identify:

Trypanosoma cruzi

Which parasite listed below causes African Sleeping Sickness?

Trypanosoma gambiense

Although not endemic in the United States, travelers and hunters in regions of East and Central Africa may acquire this blood infection from the bite of a tsetse fly. Intermittent fever, headache, joint and muscle pains may be experienced. In chronic cases, central nervous system symptoms such as mental retardation, tremors, and slow gait may lead to somnolence and "sleeping sickness." The invasive curved trypanosomes, as shown in the image of a Wright-stained peripheral blood smear, average 20 µm in length. What is the presumptive species identification of the hemo-flagellate related to this infection?

Trypanosoma rhodesiense

The stage of the organism in the illustration has an undulating membrane that extends the length of the organism, a kinetoplast, basal body, nucleus, and a flagellum. What is the most likely identification and stage of this organism?

Trypanosoma trypomastigote

The red ring at the top of the media in this tube indicates a positive indole reaction. The precursor substance in the medium from which the indole is produced is:

Tryptophan

A cerebral spinal fluid was collected from a lumbar puncture to evaluate for possible meningitis. Four tubes were collected and sent to the microbiology laboratory for analysis. Which of the four tubes is preferred for microbiology studies?

Tube 2

Which of these methods are used to identify prior exposure to Mycobacterium tuberculosis?

Tuberculin skin test (TST)

The trophozoite state of the intestinal flagellate Giardia duodenalis has what characteristic?

Two nuclei

The colony shown in the top image developed on Sabouraud's agar in 3 days when incubated at 30° C. When recovered in laboratory cultures, the source is either from the environment or a commensal contaminant. The colony has a woolly brown, gray black and white circumferential appearance, with the gray-black pigment being observed from the reverse side of the petri dish. From the microscopic appearance as illustrated in the bottom photograph, what is the most likely identification?

Ulocladium species

Smears that are appropriately stained using acridine orange should be examined using which of the following?

Ultraviolet microscopy

A 25-year-old female presented in the emergency room with an acute urethral discharge of two days duration. The image to the right shows the Gram stained smear that was obtained. Many polymorphonuclear leukocytes and intracellular and extracellular gram-negative diplococci were observed. Based on the clinical history and the Gram stain observation, what diagnosis can be made?.

Unable to determine cause of infection

This microscopic field is representative of other fields that were observed on a Gram-stained smear. Which of the following describes the quality of the smear?

Under-decolorized; Poor Quality

When identifying Trichomonas vaginalis from saline wet mounts of vaginal specimens, the organism must be observed being motile. Of the following, which one is used in identifying Trichomonas vaginalis?

Undulating membrane

A patient tested positive for cryptococcal antigen and rheumatoid factor. The results of the cryptococcal antigen should be reported as?

Uninterpretable

While working on fungal cultures, a tech encounters an organism that is orange/red in color. Immediately the tech thinks the organism is Rhodotorula species based on the color. To confirm this identification, which testing can be performed?

Urease and Inositol

A tech is working with a small, Gram-negative coccobacillus that may be Brucella spp. Which of the following tests could the tech use to rule out this organism?

Urease negative

A tech is working with a plump, bipolar staining, Gram-negative bacillus that may be Yersinia pestis. Which of the following tests could the tech use to rule out this organism?

Urease positive

Which specimen type is inoculated to media by using a quantitative isolation method?

Urine specimen

Which of the following morphological features would correspond to Phialophora verrucosum?

Urn or vase shaped phialides

Growing on the surface of the anaerobic blood agar plate illustrated in the upper image are indistinct small, gray, convex, translucent colonies free of beta hemolysis. Gram negative cocci lying singly and in clusters are seen on Gram stain, as illustrated in the lower photomicrograph. Nitrates are reduced, indole is negative, and carbohydrates are not utilized (asaccharolytic). This isolate being part of the microbiota of the mouth, upper respiratory tract and intestine. What is this organism?

Veillonella parvula

Which of the following conditions is caused by the Human Papilloma Virus?

Venereal Warts

Gram stains are performed on positive blood culture bottles. Each of the following responses correctly matches the organism with its description EXCEPT:

Very tiny, pale staining, gram-negative coccobacillus often arranging in pairs = Fusobacterium species

Which of the following organisms are Gram negative?

Vibrio

The fastidious Gram negative bacillus featured here has been recovered from individuals in pandemic outbreaks of diarrhea after ingestion of contaminated stream, lake, or well water. In many cases, life-threatening profuse diarrhea resulting in dehydration and electrolyte loss is experienced. Smooth, entire, convex light gray-yellow colonies are observed on blood agar (left upper image). Note the yellow pigmentation of the colonies growing on TCBS agar (Thiosulfate Citrate Bile Sucrose) on the right of the composite image, indicating strong acid production from sucrose. Cytochrome oxidase is also positive. Small, curved and S-shaped, gram-negative bacilli are seen on the Gram stain. From these observations, select the correct genus/species identification of this isolate.

Vibrio cholerae

What organism has a toxin that, when released, causes profuse, watery diarrhea?

Vibrio cholerae

Infections with this organism typically either present as primary septicemia or wound infections. Septicemia likely occurs after the organism is ingested while consuming shellfish. Wound infections are associated with some type of aquatic exposure. What organism does this describe?

Vibrio vulnificus

The gram negative bacillus illustrated in the lower photomicrograph was recovered from a skin wound incurred while the patient was swimming in sea water around the Western U.S. coast of the Gulf of Mexico. Note that the gray-yellow colonies grow well on blood agar (upper composite image to the left), but the colonies on TCBS agar (Thiosulfate Citrate Bile Sucrose - composite image to the right) are pale green, indicating the lack of sucrose utilization. The short, slightly curved gram negative bacilli seen in a gram stain (lower photomicrograph) are consistent with Vibrio species, but not species specific. Select the presumptive identification of this isolate.

Vibrio vulnificus

Which of the following microorganisms is associated with foodborne illness contracted from oysters and clams?

Vibrio vulnificus

Which of the following organisms is known to be a strict halophilic organism?

Vibrio vulnificus

A CSF specimen was sent to the laboratory for analysis. A glucose, protein, and cell count were performed. Based on the following results, what would be the probable cause?AnalyteResult Glucose50 mg/dLProtein100 mg/dLLeukocytes80 cells/mm3 mononuclear

Viral infection

A cerebrospinal (CSF) cell count is 1000 cells/µL. The cells on differential are predominantly lymphocytes. CSF protein is moderately elevated and the glucose is normal. No microorganisms were observed on a Gram stain smear of the CSF sediment. What is the MOST likely condition?

Viral meningitis

Acridine orange is used for:

Visualization of bacteria in specimens where debris may be present

India Ink is used to:

Visualize capsule

In the preliminary identification of the Enterobacteriaceae, it is helpful to separate the various species into tribes. Which of the following is the biochemical characteristic for which the tribe Klebsielleae can be recognized?

Voges Proskauer

Which one of the following tests would be positive in the presence of Klebsiella spp.?

Voges-Proskauer test

The urease reaction seen in the Christensen's urea agar slant on the far right indicates:

Weak activity

Which of the following corresponds to a way to prevent infection with Sporothrix schenckii?

Wear gloves when gardening

From the viruses listed below, select the one that is transmitted from birds to humans through a mosquito vector.

West Nile virus

A 27-year-old man who had recently worked as a medical laboratory scientist on the Navajo Native American reservation presented to the emergency department with high fever, diarrhea, and prostration. Axillary lymph nodes were hemorrhagic and enlarged. A smear was prepared from a lymph node aspirate and many Gram negative bacilli were noted. The bacilli demonstrated a marked bipolar staining reaction described as a "safety-pin appearance" with Wayson stain. What is the most likely identification of this organism?

Yersinia pestis

A Gram negative rod exhibiting bipolar staining was isolated from sheep blood agar after 24 hours of incubation. OxidaseNegativeUreaseNegativeCatalasePositiveIndoleNegative Which of the following species is most probable?

Yersinia pestis

A respiratory culture is submitted to the microbiology laboratory for testing. An organism displaying the following characteristics is recovered: Gram stain shows fat, Gram negative rods in single or short chains that may demonstrate bipolar staining Faster growth at 25° C Gray-white, translucent colonies on sheep blood agar (SBA) at 24 hours that turn slightly yellow and opaque at 48 hours Irregular colonies that have a "fried egg" and/or "hammered copper" appearance after 48-72 hours Catalase positive Oxidase negative Urea negative Indole negative What is the most likely organism, based on these results?

Yersinia pestis

A tech is working on a culture from an aspirated lesion. The culture grows non-hemolytic colonies with flattened edges and raised centers, resembling a fried egg on blood agar. Gram stain of the colonies shows plump Gram-negative bacilli with bipolar staining. What is the likely identification of the organism?

Yersinia pestis

Throughout history, plague pandemics have killed millions. Transmission of the human plague may still occur through bites of rodent fleas or contact with infected animals. What is the causative agent of plague?

Yersinia pestis

The photograph on the right illustrates the Rosco Diagnostica IMI/EDTA disk test and the bioMerieux MBL E test. Both tests are used to detect metallo beta-lactamse production. After viewing the results of these tests, does this organism produce metallo-beta-lactamase?

Yes

When using an iodine mount to examine a fecal specimen for intestinal protozoa or helminth ova, is it still necessary to perform a saline mount? Why?

Yes, the iodine used in an iodine mount paralyzes the motility of protozoan trophozoites.

What stain type was used to produce the image to the right?

Ziehl-Neelsen stain

In the performance of which of the following procedures may eggs with opercula be difficult to recover from or detect in stool specimens?

Zinc sulfate flotation

Which of the following is considered the technique of choice for isolating the oocysts of Isospora belli and Cryptosporidium parvum?

Zinc sulfate flotation

The organisms Klebsiella pneumonia, Enterobacter cloacae, and Escherichia coli can produce carbapenemases due to which of the following genes?

blaKPC

A D-test is performed to determine if Staphylococcus aureus or Streptococcus agalactiae has an inducible resistance to clindamycin. This inducible resistance is due to which of the following mechanisms?

erm gene

The Western Blot for HIV-1 infection identification looks for HIV p24 and what other two protein bands to confirm HIV-1 infection?

gp41 or gp160

A clean-catch midstream urine specimen from a 57-year-old woman was sent to the microbiology laboratory for culture. The patient had a history of fever, chills, and flank pain upon examiation. The urine grew out 10,000 cfu/mL of Escherichia coli. Which of the following categories would the patient be classified?

Acute, uncomplicated pyelonephritis

Four specimens are received in the laboratory at the same time. The specimens are: Urine in specimen cup for urine culture Feces in preservative for stool culture Cerebrospinal fluid for culture Synovial Fluid for culture Which specimen should be processed first?

Cerebrospinal Fluid

This intestinal parasite, which measures 5 µm, is usually not visible in samples processed using standard permanent stains. Special staining, as indicated by the coloring here, is helpful in its identification.

Cryptosporidium oocyst

Shown in this photograph are colonies growing on the surface of MacConkey agar. The pink pigment, seen both within the colonies and extending into the surrounding agar, is caused by the fermentation of:

Lactose

A beta-hemolytic gram-positive cocci, isolated from the CSF of an infant, grew on sheep blood agar under aerobic conditions and was resistant to a bacitracin disc. Which of the following tests should be performed for the presumptive identification of the organism?

Latex agglutination test

Which of the following parasites is/are considered as atrial ameba(e)?

Naegleria fowleri

A patient had a transfusion reaction to red blood cells and the remains from the unit of blood were sent to the microbiology laboratory for culture. The organism that grew was a gram-negative bacilli that was catalase and oxidase positive and was negative for gelatin hydrolysis. The organism was inoculated on a Pseudo F agar slant and incubated for 24 hours. Fluorescence was observed when using a UV light as seen in the image. This organism is most likely:

Pseudomonas putida

This member of the Enterobacteriaceae family is shown on triple sugar iron agar, lysine iron agar, urea agar, citrate agar, phenylanine deaminase agar, and motility indole ornithine agar in the photograph to the right. This organism should be identified as:

Salmonella spp.

Illustrated in the top image is a relatively rapidly growing 4-day-old colony on Sabouraud's dextrose agar incubated at 30o C. This colony was recovered as part of an environmental study. The colony has a wooly surface with distinctive black pigmentation both centrally and at the periphery, which was also visible when observed on the reverse of the Petri dish. Based on the microscopic presentation shown in the bottom image, identify this rapidly growing dematiaceous fungus.

Alternaria species

Illustrated in the top photograph is the appearance of a 4-day old fugal colony cultured from a "ringworm" cutaneous infection. Although the appearance of the colony may suggest a presumptive identification, microscopic mounts prepared from the surface hyphae must be examined, as observed in the lacto-phenol blue stained tease mount in the bottom photomicrograph. With these observations, select from the multiple choices the identification of this dermatophyte.

Microsporum canis

A patient presents with cellulitis and culture growth small beta hemoytic colonies on 5% Sheep blood agar. The gram stain of the organism is included. What is the most ikely cause of the infection.

Streptococcus pyogenes