micro Lab Ce
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
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
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
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
Campylobacter jejuni
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
Procedures that may enhance the recovery of Streptococcus pyogenes from throat cultures include:
Incorporation of sulfamethoxazole and trimethoprim in the culture media
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
Which of the following has been compared to a hockey puck when discussing its morphology on chocolate agar?
Moraxella catarrhalis
The addition of iodine to a direct and indirect wet prep is used to detect which of the following protozoan stages?
cysts
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
Which of the following causative agents is most likely associated with the "swimming pool granualoma" skin lesions depicted in the attached photograph?
Mycobacterium marinum
Why is Mycobacterium tuberculosis not seen on gram stained smears?
Mycobacterium tuberculosis has a waxy coating on its surface which prevents gram stain penetration. (this is why acid-fast staining is used)
Which organism is considered free-living amoebae?
Naegleria fowleri
Which of the following parasites is/are considered as atrial ameba(e)?
Naegleria fowleri (atrial means to settle outside of the intestinal tract)
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
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
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 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?
group a strep
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
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
The FilmArray meningitis/encephalitis panel is a multiplex panel that detects all of the following microorganism types, EXCEPT? bacteria viruses fungi parasites
parasites
The episodes of fever and chills experienced by patients suffering from malaria are known as:
paroxysms
What is the unique colony morphology feature of Rhodotorula growing on Sabouraud Dextrose Agar (SDA)?
pink-red/orange pigment
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
What color would the agar be around a colony of Staphylococcus epidermidis growing on mannitol salt agar (MSA)?
red
Edwardsiella tarda is known to be associated with which of the following animals?
reptiles
The ideal stool sample for parasitic examination is one that is freshly collected and submitted to the laboratory at:
room temp
The detection of a distinct odor is often helpful in the presumptive identification of bacterial culture isolates. Which bacterial species produces a distinctive odor of grapes?
Pseudomonas aeruginosa
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
Proteus mirabilis: 2,000 cfu/mL Klebsiella pneumoniae: 10,000 cfu/mL In which of the following urine sources would both organisms be worked up with a full sensitivity?
suprapubic aspiration
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 Dr 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
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 Aspergillus species show biseriate with phialides covering the entire surface of a spherical vesicle with black conidia as microscopic morphological features?
Aspergillus niger
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.
Amikacin resistant, Gentamicin or tobramycin sensitive, Carbapenem resistant
Bordet-Gengou plates are used to isolate:
Bordetella pertussis
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
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
Which of these parasites are hermaphroditic in their adult phase?
Clonorchis sinensis
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
Which of the following dematiaceous fungal species produce conidia in clusters?
Exophiala species
Which parasite corresponds with the sandfly as its insect vector?
Leishmania spp.
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
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
Which of the following organisms is an obligate intracellular parasite?
Rickettsia
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
This case is typical of Yersinia enterocolitica and the biochemical reactions listed are consistent for this organism. Y. enterocolitica generally presents as severe lower abdominal pain mimicking appendicitis, but infects the mesenteric lymph nodes and may infect the appendix and ileum.
*just a little info about one above*
Proteus mirabilis may produce a "burnt chocolate" smell. Staphylococcus aureus may produce odor of old socks. Streptococcus anginosus may produce a butterscotch odor.
*may be on there was in a feedback thingy*
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
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
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
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
Which of the following organisms causes Q Fever
Coxiella burnetii
The body of an adult cestode consists of segments called:
Proglottids
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 old
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
When a lumbar puncture is performed, what volume of spinal fluid is needed for optimal recovery of meningitis causing organisms?
5-10ml
Which of the following enzymes, produced by Staphylococcus aureus is responsible for preventing penicillin antibiotics from being effective?
Beta-lactamase
The avoidance of laboratory diagnosis techniques that utilize water is recommended for the identification of which of these parasites?
Blastocystis hominis
The following Clostridium difficile virulence factor is significant in the cause of antibiotic-associated pseudomembranous colitis:
Cytotoxin A or B
The eggs of this parasite arrange themselves in membrane-enclosed clusters known as packets: (i call them the grape cluster)
Dipylidium caninum
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
Which two antibiotics are used to confirm the presence of carbapenemase production in Enterobacteriaceae?
Ertapenem and Meropenem
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 of the following Mycobacterium species is closely associated with infections in HIV positive patients?
M. avium-intracellulare complex
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: Haemophilus influenzae Morazella lacunata Neisseria gonorrhoeae Acientobacter lwoffii
Moraxella lacunata
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
Which of the following conditions is a category B condition in a HIV-infected adult? peripheral neuropathy kaposi's sarcoma esophageal candidiasis recurrent bacterial pneumonia
Peripheral neuropathy (the rest are Category C conditions with are associated with AIDS)
Which of the following viral families contains DNA as its nucleic acid?
Poxviridae
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
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.
Which of the following is the most common etiologic agent identified in prosthetic valve endocarditis?
Staphylococcus epidermidis
Which of the following organisms is the leading cause of bacterial meningitis in infants, young children, and adults in the United States?
Strep pneumoniae
The microscopic view of a Gram stained sputum specimen reveals lancet-shaped, Gram positive diplococci. What presumptive identification may be made?
Streptococcus pneumoniae
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 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
What is the purpose of a trichrome stain?
To identify protozoan trophozoites and cysts in fecal samples.
In the following list of organisms, which organism is considered cryophilic (can grow as low as 4° C)?
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 (CEFSULODIN,IRGASAN,NOVOBIOCIN= CIN AGAR FOR YERSINITA)
Which of the following is considered the technique of choice for isolating the oocysts of Isospora belli and Cryptosporidium parvum?
Zinc sulfate flotation
What is the first test always performed on organisms growing on solid or liquid mycobacterial media?
acid-fast staining
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 used to determine if a person has had a recent infection with Strep pyogenes?
antistreptolysin O(ASO)
A 3-year old girl was brought to the ER with a temperature of 103ºF, lethargy, and cervical rigidity. Three tubes of cloudy CSF were delivered to the Lab, and preliminary test results showed: WBC: 4,500/µL Differential: 88% neutrophilsGlucose: 15 mg/dL 12% lymphocytesProtein: 140 mg/dLGram stain: No organisms observed From these results, what preliminary diagnosis SHOULD the physician consider?
bacterial meningitis
The following is the vector for the transmission of Onchocerca volvulus:
black flies
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 inhalation anthrax. What should the tech indicate is a proper specimen for collection to detect inhalation anthrax?
blood(to test for antigens and blood cultures to be done)
All of the following are commercial methodologies that Chlamydia and Neisseria identification have been based on, EXCEPT? ligase chain reaction hybrid capture branched chain dna technology strand displacement amplification
branched chain dna technology
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
