microbiolog

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

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

Branched chain DNA technology

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

Bronchial washings

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)

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

An 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

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

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

The infectious disease process in which large numbers of activated macrophages and histiocytes are collected at the site of inflammation is called?

Granulomatous

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

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

Which bacterial species is a common agent of neonatal bacteremia?

Listeria monocytogenes

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

The appropriate media for the isolation of anaerobic bacteria from any source would normally include all of the following except:

MacConkey agar

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)

Which of the following best describes the benefits of the RPR or VDRL tests:

Monitoring course of treatment

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

MacConkey agar without crystal violet is a culture medium useful in the presumptive identification of:

Mycobacterium fortuitum

Smears that are appropriately stained using acridine orange should be examined using which of the following?

Ultraviolet microscopy

A patient tested positive for cryptococcal antigen and rheumatoid factor. The results of the cryptococcal antigen should be reported as?

Uninterpretable

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

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

Use cytocentrifugation to prepare the slide

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

Use of selenite enrichment broth

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

The urease reaction seen in the Christensen's urea agar slant on the far right indicates:

Weak activity

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

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 view of a Gram-stained sputum specimen reveals lancet-shaped, Gram-positive diplococci. What presumptive identification may be made?

Streptococcus pneumoniae

A patient presents with cellulitis and culture growth small beta hemolytic colonies on 5% Sheep blood agar. The gram stain of the organism is included. What is the most likely cause of the infection?

Streptococcus pyogenes

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

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

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

Bismuth sulfite agar

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

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

Bordetella bronchiseptica

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

Nasopharyngeal swab

When a corrected report needs to be made, which of the following is required?

Notify the physician of the erroneous report

In the Escherichia coli 0157:H7 serotype. The 0157 portion of the serotype refers to which of the following?

O somatic antigen

What is one of the BIGGEST challenges with isolating Francisella?

Organism growth is slow.

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

Which of the following is a rapid latex agglutination method for detecting Methicillin-Resistant Staphylococcus aureus (MRSA)?

PBP2a

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

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

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-lactamase production. After viewing the results of these tests, does this organism produce metallo-beta-lactamase?

Yes

Different species of Neisseria can be differentiated from each other by:

Carbohydrate utilization

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

Which of the following is a selective media recommended for the isolation of Clostridioides 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)

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

Actinomyces spp.

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

Bacteroides fragilis

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

1 : 10

The minimum time of retention for microbiology test reports is?

2 years

The organism Acinetobacter baumannii is known to have caused which of the following outbreaks?

Afghanistan and Iraq U.S. soldiers outbreak

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.

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

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

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

Bacillus spp.

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

Bacillus subtilis

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

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 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

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

Cerebral spinal fluid (CSF)

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

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

Cerebrospinal fluid (CSF)

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

Charcoal and yeast extract

The serum medium and methylene blue stain originally described by Loeffler are both helpful in the identification of:

Corynebacterium diphtheriae

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

The modified acid-fast stain is primarily used to identify:

Cryptosporidium oocysts

Which statement about bacterial culture for Clostridioides (Clostridium) difficile is TRUE?

Culture on appropriate media provides an effective means of recovering the organism.

Bacitracin susceptibility testing is useful for:

Distinguishing staphylococci from micrococci

The microbiology supervisor noticed that a higher number of positive 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

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

Drainage bag from nephrostomy catheter

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

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 following is the most likely identification?

Elizabethkingia (Flavobacterium) meningosepticum

Which phrase describes enrichment media?

Encourages the growth of specific types of organisms.

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 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

Which two antibiotics are used to confirm the presence of carbapenemase production in Enterobacteriaceae?

Ertapenem and Meropenem

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

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 rhusiopathiae

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. Gram-negative, oxidase-negative rods (bacilli) grew as lactose fermenters on MacConkey agar and 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

To screen for the Methicillin-Resistant Staphylococcus aureus, all of the following collection sites are appropriate EXCEPT?

Eye

Which of the following is a confirmatory test for syphilis?

FTA-ABS

A positive RPR test and a negative FTA-ABS test is most likely the result of:

False-positive reaction

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

All of the following are characteristics of Burkholderia pseudomallei, EXCEPT?

Fat, gram-postive rod

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.

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.

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

Francisella

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

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

Gram-positive bacteria

What is the medium of choice for isolating Gardnerella vaginalis?

Human blood bilayer Tween (HBT) agar

The selective medium XLD is seen in this illustration. What is the significance of the black colonies observable on this plate?

Hydrogen sulfide production

Review each matched pair. Each correctly matches the bacterial species with its Gram staining reaction and morphology EXCEPT:

Image B = Moraxella catarrhalis

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

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

Incorporation of sulfamethoxazole and trimethoprim in the culture media

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

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

Intracellular gram-negative diplococci

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 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 indicates 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"

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

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

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.

Klebsiella pneumoniae

The reactions in a portion of the API strip, shown in the photograph, most closely identifies which organism?

Klebsiella pneumoniae

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

The Thayer-Martin agar plate seen in this illustration exhibits marked growth. The most likely organism found here would be:

Neisseria gonorrhoeae

An organism grew out of a spinal shunt. The protocol for the growth of this organism is to notify infection control and the public health department. In addition, any healthcare 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

Which one of the following results is typical of Campylobacter jejuni?

Optimal growth at 42 ºC

MacConkey agar contains all of the following except:

Penicillin

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

Peptostreptococcus anaerobius

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

Pericardial fluid

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

Peritonsillar fossae

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

Phenicols

Based on the picture and the criteria below, how would the Gram stain be interpreted?

Pink, 1 cell thick, No, Yes

The condition most likely to predispose a person to septicemia by viridans streptococci is:

Poor oral hygiene

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?

Porphyromonas asaccharolytica

A tech working in microbiology 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 with 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 consider as an urgent result?

Positive blood culture showing Gram positive cocci

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

All of the following sample types should be accepted for a lower respiratory culture, EXCEPT:

Posterior pharynx swab

All of the following are statements concerning the gram stain. Which of the following is a TRUE statement?

Presumptive evidence is provided.

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

To screen for Vancomycin-Resistant Enterococci, which of the following culture sites is most appropriate?

Rectal

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.

Which of the following Streptococcus spp. exhibits a positive bile solubility test?

S. pneumoniae

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

Scalded Skin Syndrome

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.

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

What is the most common agent of infection in CSF shunts?

Stahpylococcus sp.

The McFarland Comparison Card shown in the illustration is used to:

Standardize concentrations of organisms

Which of the following gastrointestinal pathogens has an incubation period of 1-8 hours?

Staphylococcus aureus

Which of the following organisms is most likely pictured in the Gram stain photomicrograph taken from a broth?

Staphylococcus aureus

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

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

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

When an unpreserved urine specimen cannot be cultured immediately, which storage method is most appropriate?

Stored in the refrigerator at 4° C for up to 24 hours

Examine the gram stain illustration. The organism labeled "A" is most likely which of the following?

Streptococcus pneumoniae

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

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

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 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

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.

A vaginal swab for anaerobic culture is received in the laboratory. How should this specimen be handled?

The specimen should be rejected

All of the following statements concerning Rickettsia species are true, EXCEPT:

They are cultured in many hospital laboratories.

All of the following specimens would be considered suitable for anaerobic culture, EXCEPT?

Throat swab

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 specimen type should be gently minced before inoculating fungal media?

Tissue

How would you classify the organism on this Gram stain?

Yeast

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

Yersinia enterocolitica

A Gram negative rod exhibiting bipolar staining was isolated from sheep blood agar after 24 hours of incubation.

Yersinia pestis

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

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

Acid-fast positive

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 to?

Aminoglycosides

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

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

Haemophilus influenzae

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

Bacitracin susceptibility

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

Bile solubility

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

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

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

Check to ensure autoverification of results is working correctly

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 the addition of zinc dust, as shown in the right tube of the pair labeled "Nit"), the most likely identification is:

Chryseobacterium spp.

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

Eikenella corrodens is associated with which of the following?

Clenched fist infection

Which of the following organisms is gram-positive?

Clostridioides difficile

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 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

Which of the following media would you use to isolate Francisella tularensis:

Cystine-heart agar

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

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

Which of the following organisms shows a characteristic "test-tube brush-like" pattern at 22 degrees Celsius?

Erysipelothrix rhusiopathiae

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

Gram

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

Gram positive cocci in pairs.

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

Gram's iodine

How would this Gram-stained smear be correctly described?

Gram-negative bacilli

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 X and V Factor 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

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

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

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

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

Indole production

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

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

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

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

Legionella pneumophila

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 the 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

Identification of intestinal microsporidial spores is usually done by using which of the listed stains?

Modified trichrome stain

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

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 locate any material (cells or bacteria) on the slide. How should the tech proceed?

Prepare a new slide by using cytocentrifugation

Sodium thiosulfate is often added to selective culture media to:

Provide sulfur atoms for H2S positive isolates

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

Which of the following is a nonfermenter?

Pseudomonas aeruginosa

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

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

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

Trichomonas vaginalis

Which one of the following tests would be positive in the presence of Klebsiella spp.?

Voges-Proskauer test

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

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 the nucleic acid to aid in the detection of cell wall deficient organisms?

Acridine Orange

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

What system is used in the clinical laboratory to monitor a patient's current clinical values for a test with previous values?

Delta checks

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

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

Haemophilus spp.

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

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

The minimum time of retention for microbiology instrument records is?

Life of the instrument

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).

Select the most appropriate identification of a non-lactose fermenting Enterobacteriaceae based on the following test results:

Providencia stuartii

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

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

On sheep blood agar, Haemophilus influenzae may exhibit satellitism around all of the following bacteria, EXCEPT:

Pseudomonas spp.

The pigment produced on the King's medium agar plate illustrated in this photograph is:

Pyocyanin

The OF dextrose activity is a key initial assessment in the presumptive identification of the nonfermentative gram-negative bacilli.

Ralstonia pickettii (formerly Burkholderia pickettii)

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

Amikacin resistant, Gentamicin or tobramycin sensitive, Carbapenem-resistant

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