BOC Microbiology Questions and Answers
100% Solved
A penicillin-resistant Neisseria gonorrhoeae produces:
A. alpha-hemolysin
B. beta-lactamase
C. enterotoxin
D. coagulase Correct Answer: B
Which selective medium is used for the isolation of gram-positive microorganism?
A. Columbia CNA with 5% sheep blood
B. trypticase soy agar with 5% sheep blood
C. eosin methylene blue
D. modified Thayer-Martin Correct Answer: A
The most sensitive substrate for the detection of beta-lactamases is:
A. penicillin
B. ampicillin
,C. cefoxitin
D. nitrocefin Correct Answer: D
A Staphylococcus aureus isolate has an MIC of 4 ug/mL to oxacillin. There is uncertainty as to
whether this represents an oxacillin (heteroresistant) resistant strain or hyperproducer of beta-
lactamase.
Strain; Oxacillin; Amoxicillin-clavulanic acid
-Strain A: sus;sus
-Strain B: sus; res
-Stain C: res; sus
-Strain D: res; res
Based on the above results for oxacillin and amoxicillin-clavulanic acid, which strain is
heteroresistant?
A. stain A
B. strain B
C. strain C
D. strain D Correct Answer: D
,An Enterococcus isolated from multiple blood cultures in a patient endocarditis should be:
A. screened for high level aminoglycoside resistance
B. checked fo tolerance
C. assayed for serum antimicrobial activity
D. tested for beta-lactamase production Correct Answer: A
In the Kirby-Bauer disc diffusion susceptibility test, which variable is critical when testing
Pseudomonas species for antibiotic susceptibility to aminoglycosides?
A. incubation temperature
B. duration of incubation
C. cation content of media
D. depth of agar Correct Answer: C
The procedure that assures the most accurate detection of mecA-mediated oxacillin resistance
in routine broth microdilution susceptibility testing against S. aureus is:
A. addition of 4% NaCl
B. incubation at 30 C
C. incubation for 48 hours
, D. use of cefoxitin for testing Correct Answer: D
When performing a stool culture, a colony type typical of an enteric pathogen is subcultured on
a blood agar plate. The resulting pure culture is screened with several tests to obtain the
following results:
-TSI: acid butt, alkaline slant, no gas, no H2S
-phenylalanine deaminase: negative
-motility: positive
-serological typing: Shigella flexneri (shigella subgroup B)
The serological typing is verified with new kit and controls. The best course of action would be
to:
A. report the organism as Shigella flexneri without further testing
B. verify reactivity of motility medium with positive and negative controls
C. verify reactivity of the TSI slants with positive and negative controls for H2S production
D. verify reactivity of phenylalanine deaminase with positive and negative controls
Correct Answer: B
100% Solved
A penicillin-resistant Neisseria gonorrhoeae produces:
A. alpha-hemolysin
B. beta-lactamase
C. enterotoxin
D. coagulase Correct Answer: B
Which selective medium is used for the isolation of gram-positive microorganism?
A. Columbia CNA with 5% sheep blood
B. trypticase soy agar with 5% sheep blood
C. eosin methylene blue
D. modified Thayer-Martin Correct Answer: A
The most sensitive substrate for the detection of beta-lactamases is:
A. penicillin
B. ampicillin
,C. cefoxitin
D. nitrocefin Correct Answer: D
A Staphylococcus aureus isolate has an MIC of 4 ug/mL to oxacillin. There is uncertainty as to
whether this represents an oxacillin (heteroresistant) resistant strain or hyperproducer of beta-
lactamase.
Strain; Oxacillin; Amoxicillin-clavulanic acid
-Strain A: sus;sus
-Strain B: sus; res
-Stain C: res; sus
-Strain D: res; res
Based on the above results for oxacillin and amoxicillin-clavulanic acid, which strain is
heteroresistant?
A. stain A
B. strain B
C. strain C
D. strain D Correct Answer: D
,An Enterococcus isolated from multiple blood cultures in a patient endocarditis should be:
A. screened for high level aminoglycoside resistance
B. checked fo tolerance
C. assayed for serum antimicrobial activity
D. tested for beta-lactamase production Correct Answer: A
In the Kirby-Bauer disc diffusion susceptibility test, which variable is critical when testing
Pseudomonas species for antibiotic susceptibility to aminoglycosides?
A. incubation temperature
B. duration of incubation
C. cation content of media
D. depth of agar Correct Answer: C
The procedure that assures the most accurate detection of mecA-mediated oxacillin resistance
in routine broth microdilution susceptibility testing against S. aureus is:
A. addition of 4% NaCl
B. incubation at 30 C
C. incubation for 48 hours
, D. use of cefoxitin for testing Correct Answer: D
When performing a stool culture, a colony type typical of an enteric pathogen is subcultured on
a blood agar plate. The resulting pure culture is screened with several tests to obtain the
following results:
-TSI: acid butt, alkaline slant, no gas, no H2S
-phenylalanine deaminase: negative
-motility: positive
-serological typing: Shigella flexneri (shigella subgroup B)
The serological typing is verified with new kit and controls. The best course of action would be
to:
A. report the organism as Shigella flexneri without further testing
B. verify reactivity of motility medium with positive and negative controls
C. verify reactivity of the TSI slants with positive and negative controls for H2S production
D. verify reactivity of phenylalanine deaminase with positive and negative controls
Correct Answer: B
