Micro Progress Flashcards
Flocked swab:
a. Cotton
b. Gauze
c. Cotton and gauze
d. Nylon
d. Nylon
The steam autoclave method of sterilization:
a. Uses 15 lbs of pressure for 15 minutes
b. Utilizes dry heat for 20 minutes
c. Produces a maximum temperature of 100ºC
d. Requires a source of ethylene oxide
a. Uses 15 lbs of pressure for 15 minutes
The most important diagnostic tool in treating patients with clinical infections in the emergency department:
a. AFB stain
b. Culture
c. Gram stain
d. IMVic reaction
c. Gram stain
Additional tests to be included with the IMViC reaction:
a. Bacitracin and SXT susceptibility
b. Catalase and coagulase
c. Motility and H2S
d. Oxidase and urease
c. Motility and H2S
Salmonella Shigella (SS) Agar is a modification of:
a. BAP
b. CAP
c. DCA
d. EMB
c. DCA
Salmonella Shigella (SS) Agar is a modification of the Deoxycholate Citrate Agar.
Cary-Blair indicator changes from red to yellow color:
a. Buffering capacity was overcomed
b. Change in the pH of the medium
c. Low temperature
d. Presence of contaminants
a. Buffering capacity was overcomed
When cultured in thioglycollate broth, these organisms grow slightly below the surface where oxygen concentrations are lower than atmospheric concentrations
a. Aerotolerant anaerobes
b. Facultative anaerobes
c. Microaerophilic organisms
d. Obligate aerobes
c. Microaerophilic organisms
Which one of the following specimen requests is acceptable?
a. Feces submitted for anaerobic culture
b. Foley catheter tip submitted for aerobic culture
c. Rectal swab submitted for direct smear for gonococci
d. Urine for culture of acid-fast bacilli
d. Urine for culture of acid-fast bacilli
Which of the following is the most appropriate method for collecting a urine specimen from a patient with an indwelling catheter?
a. Remove the catheter, cut the tip, and submit it for culture
b. Disconnect the catheter from the bag, and collect urine from the terminal end of the catheter
c. Collect urine directly from the bag
d. Aspirate urine aseptically from the catheter tubing
d. Aspirate urine aseptically from the catheter tubing
A liquid fecal specimen from a three-month-old infant is submitted for microbiological examination. In addition to culture on routine media for Salmonella and Shigella, this specimen should be routinely:
a. Examined for the presence of Entamoeba hartmanni
b.Examined for the presence of Camylobacter sp
c. Screened for the detection of enterotoxigenic Escherichia coli
d. Placed in thioglycollate broth to detect Clostridium botulinum
b.Examined for the presence of Camylobacter sp
Composition of 0.5 McFarland standard:
a. 1% sulfuric acid and 2.175% barium chloride
b. 1% sulfuric acid and 1.175% barium chloride
c. 1% hydrochloric acid and 2.175% barium chloride
d. 1% hydrochloric acid and 1.175% barium chloride
b. 1% sulfuric acid and 1.175% barium chloride
Standard agar depth of the Mueller-Hinton agar:
a. 1 to 2 mm
b. 3 to 5 mm
c. 6 to 8 mm
d. 7 to 9 mm
b. 3 to 5 mm
Susceptibility testing performed on quality control organisms using a new media lot number yielded zone sizes that were too large for all antibiotics tested. The testing was repeated using media from a previously used lot number, and all zone sizes were acceptable. Which of the following best explains the unacceptable zone sizes?
a. The antibiotic disks were not stored with the proper desiccant
b. The depth of the media was too thick
c. The depth of the media was too thin
d. The antibiotic disks were not properly applied to the media
c. The depth of the media was too thin
Quality control results for disk diffusion susceptibility tests yield the following results: aminoglycoside zones too small and penicillin zones too large. This is most likely due to the:
a. Inoculum being too heavy
b. Inoculum being too light
c. pH of Mueller-Hinton agar being too low
d. Calcium and magnesium concentration in the agar being too high
c. pH of Mueller-Hinton agar being too low
In disk diffusion susceptibility testing, as an antimicrobial agent diffuses away from the disk, the concentration of antibiotic is:
a. Increased
b. Decreased
c. Unchanged
d. Inoculum dependent
b. Decreased
After satisfactory performance of daily disk diffusion susceptibility quality control is documented, the frequency of quality control can be reduced to:
a. Twice a week
b. Every week
c. Every other week
d. Every month
b. Every week
An outbreak of Staphylococcus aureus has occurred in a hospital nursery. In order to establish the epidemiological source of the outbreak, the most commonly used typing method is:
a. Pulsed-field gel electrophoresis
b. Serological typing
c. Coagulase testing
d. Catalase testing
a. Pulsed-field gel electrophoresis
The organism most commonly associated with neonatal purulent meningitis is:
a. N. meningitidis
b. S. pneumoniae
c. S. agalactiae
d. S. pyogenes
c. S. agalactiae
One of the enterotoxins produced by enterotoxigenic Escherichia coli in traveler’s diarrhea is similar to a toxin produced by:
a. Clostridium perfringens
b. Clostridium difficile
c. Vibrio cholerae
d. Yersinia enterocolitica
c. Vibrio cholerae
Which of the following sets of tests best differentiates Salmonella and Citrobacter species?
a. KCN, malonate, beta-galactosidase, lysine decarboxylase
b. Dulcitol, citrate, indole, H2S production
c. Lactose, adonitol, KCN, motility
d. Lysine decarboxylase, lactose, sucrose, malonate, indole
a. KCN, malonate, beta-galactosidase, lysine decarboxylase
The Oriental rat flea, Xenopsylla cheopis, can be involved in transmitting which of the following microorganisms?
a. Bartonella quintana
b. Plasmodium spp.
c. Rickettsia prowazeki
d. Yersinia pestis
d. Yersinia pestis
Oxidase positive, urease negative:
a. Bordetella bronchiseptica
b. Bordetella pertussis
c. Bordetella parapertussis
d. All of these
b. Bordetella pertussis
A culture from an infected dog bite on a small boy’s finger yielded a small, gram-negative coccobacillus that was smooth, raised and beta-hemolytic on blood agar. The isolate grew on MacConkey agar, forming colorless colonies. The organism was motile, catalase positive, oxidase positive, reduced nitrate, and was urease positive within 4 hours. No carbohydrates were fermented. The most likely identification of this isolate is:
a. Brucella canis
b. Yersinia pestis
c. Francisella tularensis
d. Bordetella bronchiseptica
d. Bordetella bronchiseptica
While swimming in a lake near his home, a young boy cut his foot, and an infection developed. The culture grew a nonfastidious gram-negative, oxidase positive, beta hemolytic, motile bacilli that produced deoxyribonuclease. The most likely identification is:
a. Enterobacter cloacae
b. Serratia marcescens
c. Aeromonas hydrophila
d. Escherichia coli
c. Aeromonas hydrophila
A community hospital microbiology laboratory is processing significant numbers of stool cultures because of an outbreak of diarrhea following heavy rains and flooding in the country. A media that should be incorporated in the plating protocol is:
a. Colistin nalidixic acid for Listeria
b. MacConkey agar with sorbitol for Campylobacter
c. Mannitol salt agar for Enterococcus species
d. Thiosulfate citrate bile salts sucrose for Vibrio species
d. Thiosulfate citrate bile salts sucrose for Vibrio species
Stool specimens suspected of containing Vibrio spp. should be collected and transported only in:
a. Amies medium
b. Cary-Blair medium
c. Stuart’s medium
d. Transgrow medium
b. Cary-Blair medium
Catalase positive, lactose negative, xylose positive:
a. Haemophilus aegypticus
b. Haemophilus ducreyi
c. Haemophilus parainfluenzae
d. Haemophilus influenzae
d. Haemophilus influenzae
The best procedure to differentiate Listeria monocytogenes from Corynebacterium species is:
a. Catalase
b. Motility at 25C
c. Motility at 35C
d. Gram stain
b. Motility at 25C
A patient has a suspected diagnosis of subacute bacterial endocarditis. His blood cultures grow non-spore-forming pleomorphic gram-positive bacilli only in the anaerobic bottle. What test(s) will give a presumptive identification of this microorganism?
a. Beta-hemolysis and oxidase
b. Catalase and spot indole
c. Esculin hydrolysis
d. Gelatin hydrolysis
b. Catalase and spot indole
Colonies appear shiny and mucoid because of the presence of a polysaccharide capsule:
a. Candida albicans
b. Cryptococcus neoformans
c. Malassezia furfur
d. Histoplasma capsulatum
b. Cryptococcus neoformans
LATEX AGGLUTINATION for cryptococcal _____ is now recommended test for Cryptococcus neoformans.
a. Polysaccharide capsule
b. Antigen
c. Antibody
d. Nucleic acids
b. Antigen
A mold grown at 25C exhibited delicate septate hyaline hyphae and many conidiophores extending at right angles from the hyphae. Oval, 2-5 um conidia were formed at the end of the conidiophores giving a flowerlike appearance. In some areas “sleeves” of spores could be found along the hyphae as well. A 37C culture of this organism produced small, cigar-shaped yeast cells. This organism is most likely:
a. Histoplasma capsulatum
b. Sporothrix schenckii
c. Blastomyces dermatitidis
d. Coccidioides immitis
b. Sporothrix schenckii
Virulence factors include aflatoxin, serine protease and aspartic acid proteinase:
a. Aspergillus spp.
b. Blastomyces dermatitidis
c. Cryptococcus neoformans
d. Histoplasma capsulatum
a. Aspergillus spp.
Most often, ______ are “dead-end” hosts.
a. Amphibians
b. Birds
c. Humans
d. Rodents
c. Humans
Delay in the processing of fluid specimens requires dilution in a viral transport medium before storage:
a. 1: 2 to 1:5
b. 1:10 to 1:20
c. 1:50 to 1:100
d. 1:100 to 1:200
a. 1: 2 to 1:5
The most sensitive method for the detection of β-lactamase in bacteria is by the use of:
a. Chromogenic cephalosporin
b. Penicillin
c. Oxidase
d. Chloramphenicol acetyltransferase
a. Chromogenic cephalosporin
According to the Kirby–Bauer standard antimicrobial susceptibility testing method, what should be done when interpreting the zone size of a motile, swarming organism such as Proteus species?
a. The swarming area should be ignored
b. The results of the disk diffusion method are invalid
c. The swarming area should be measured as the growth boundary
d. The isolate should be retested after diluting to a 0.05 McFarland standard
a. The swarming area should be ignored
Antimicrobial susceptibility testing of anaerobes is done by which of the following methods?
a. Broth disk elution
b. Disk agar diffusion
c. Microtube broth dilution
d. β-Lactamase testing
c. Microtube broth dilution
Cerebrospinal fluid (CSF) should be cultured immediately, but if delayed the specimen should be:
a. Refrigerated at 4°C to 6°C
b. Frozen at –20°C
c. Stored at room temperature for no longer than 24 hours
d. Incubated at 37°C and cultured as soon as possible
d. Incubated at 37°C and cultured as soon as possible
Select the method of choice for recovery of anaerobic bacteria from a deep abscess.
a. Cotton fiber swab of the abscess area
b. Skin snip of the surface tissue
c. Needle aspirate after surface decontamination
d. Swab of the scalpel used for débridement
c. Needle aspirate after surface decontamination
Anaerobic bacteria are routinely isolated from all of the following types of infections except:
a. Lung abscesses
b. Brain abscesses
c. Dental infections
d. Urinary tract infections
d. Urinary tract infections
Prereduced and vitamin K1-supplemented blood agar plates are recommended isolation media for:
a. Mycobacterium marinum and Mycobacterium avium intracellulare
b. Bacteroides, Peptostreptococcus, and Clostridium spp.
c. Proteus spp.
d. Enterococcus spp.
b. Bacteroides, Peptostreptococcus, and Clostridium spp.
Which of the following is the medium of choice for the selective recovery of gram-negative anaerobes?
a. Kanamycin–vancomycin (KV) agar
b. Phenylethyl alcohol (PEA) agar
c. Cycloserine–cefoxitin–fructose agar (CCFA)
d. THIO broth
a. Kanamycin–vancomycin (KV) agar
Methods other than packaged microsystems used to identify anaerobes include:
a. Antimicrobial susceptibility testing
b. Gas–liquid chromatography (GLC)
c. Special staining
d. Enzyme immunoassay
b. Gas–liquid chromatography (GLC)
Semisolid transport media such as Amies, Stuart, or Cary–Blair are suitable for the transport of swabs for culture of most pathogens except:
a. Neisseria gonorrhoeae
b. Enterobacteriaceae
c. Campylobacter fetus
d. Streptococcus pneumoniae
a. Neisseria gonorrhoeae
Colistin–nalidixic acid agar (CNA) is used primarily for the recovery of:
a. Neisseria species
b. Enterobacteriaceae
c. Pseudomonas aeruginosa
d. Staphylococcus aureus
d. Staphylococcus aureus