BOC Microbiology Exam Study Questions with
100% Correct Answers | Verified
An Enterococcus isolated from multiple blood cultures in a patient endocarditis should
be:
a. screened for high level aminoglycoside resistance
b. checked for tolerance
c. assayed for serum antimicrobial activity
d. tested for beta-lactamase production - ✔✔a. screened for high level
aminoglycoside resistance
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 - ✔✔d. use of cefoxitin for testing
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 obstain 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 -
✔✔b. verify reactivity of motility medium with positive and negative controls
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
Which of the following is the most appropriate specimen source and primary media
bettery?
a. endocervical- chocolate, Martin Lewis
b. sputum- sheep blood, Thayer-Martin, KV-laked blood
c. CSF- Columbia CNA, MacConkey
d. urine- sheep blood, chocolate, Columbia CNA - ✔✔a. endocervical- chocolate,
Martin Lewis
The ONPG test allows organisms to be classified as a lactose fermenter by testing for
which of the following?
a. permease
b. beta-galactosidase
c. beta-actamase
,d. phosphatase - ✔✔b. beta-galactosidase
Sodium bicarbonate and sodium citrate are components of which of the follwoing?
a. JEMBEC system
b. MTM agar
c. MYC medium
d. ML agar - ✔✔a. JEMBEC system
Chocolate agar base containing vancomycin, colistin, anisomycin, and trimethoprim is
also known as:
a. EMB agar
b. modified Thayer-Martin agar
c. Columbia CNA agar
d. Martin Lewis Agar - ✔✔d. Martin Lewis agar
- for Candida
When evaluating a new susceptibility testing system, if the new system characterizes a
susceptible isolate as resistant, this is termed a:
a. very major error
b. major error
c. minor error
d. acceptable error - ✔✔b. major error
-Very major error: resistant isolate is characterized as susceptible
-major error: susceptible isolate characterized as resistant
-minor error: susceptible or resistant isolate characterized as intermediate or
intermediate isolate as susceptible or resistant
, Which of the following methods is inadequate for the detection of vancomycin-
intermediate S. aureus?
a. broth macrodilution
b. agar dilution
c. gradient ddiffusion
d. disk diffusion - ✔✔d. disk diffusion
-Just wont work for vancomycin susceptibility for S aureus
First-generation cephalosporins can be adequately represented by:
a. cefotetan
b. ceftriaxone
c. cephalothin
d. cefoxitin - ✔✔c. cephalothin
Which one of the following organisms does not require susceptibility testing to the
antimicrobial indicated when isolated from a clinically significant source?
a. Staphylococcus aureus- clindamycin
b. Proteus mirabilis- gentamicin
c. Streptococcus pyogenes- penicillin
d. Escherichia coli- levofloxacin - ✔✔c. Streptococcus pyogenes- penicillin
-Resistance has not been documented
Which of the following antibiotics would routinely be tested and reported for isolates of
Pseudomonas aeruginosa?
a. penicillin
100% Correct Answers | Verified
An Enterococcus isolated from multiple blood cultures in a patient endocarditis should
be:
a. screened for high level aminoglycoside resistance
b. checked for tolerance
c. assayed for serum antimicrobial activity
d. tested for beta-lactamase production - ✔✔a. screened for high level
aminoglycoside resistance
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 - ✔✔d. use of cefoxitin for testing
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 obstain 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 -
✔✔b. verify reactivity of motility medium with positive and negative controls
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
Which of the following is the most appropriate specimen source and primary media
bettery?
a. endocervical- chocolate, Martin Lewis
b. sputum- sheep blood, Thayer-Martin, KV-laked blood
c. CSF- Columbia CNA, MacConkey
d. urine- sheep blood, chocolate, Columbia CNA - ✔✔a. endocervical- chocolate,
Martin Lewis
The ONPG test allows organisms to be classified as a lactose fermenter by testing for
which of the following?
a. permease
b. beta-galactosidase
c. beta-actamase
,d. phosphatase - ✔✔b. beta-galactosidase
Sodium bicarbonate and sodium citrate are components of which of the follwoing?
a. JEMBEC system
b. MTM agar
c. MYC medium
d. ML agar - ✔✔a. JEMBEC system
Chocolate agar base containing vancomycin, colistin, anisomycin, and trimethoprim is
also known as:
a. EMB agar
b. modified Thayer-Martin agar
c. Columbia CNA agar
d. Martin Lewis Agar - ✔✔d. Martin Lewis agar
- for Candida
When evaluating a new susceptibility testing system, if the new system characterizes a
susceptible isolate as resistant, this is termed a:
a. very major error
b. major error
c. minor error
d. acceptable error - ✔✔b. major error
-Very major error: resistant isolate is characterized as susceptible
-major error: susceptible isolate characterized as resistant
-minor error: susceptible or resistant isolate characterized as intermediate or
intermediate isolate as susceptible or resistant
, Which of the following methods is inadequate for the detection of vancomycin-
intermediate S. aureus?
a. broth macrodilution
b. agar dilution
c. gradient ddiffusion
d. disk diffusion - ✔✔d. disk diffusion
-Just wont work for vancomycin susceptibility for S aureus
First-generation cephalosporins can be adequately represented by:
a. cefotetan
b. ceftriaxone
c. cephalothin
d. cefoxitin - ✔✔c. cephalothin
Which one of the following organisms does not require susceptibility testing to the
antimicrobial indicated when isolated from a clinically significant source?
a. Staphylococcus aureus- clindamycin
b. Proteus mirabilis- gentamicin
c. Streptococcus pyogenes- penicillin
d. Escherichia coli- levofloxacin - ✔✔c. Streptococcus pyogenes- penicillin
-Resistance has not been documented
Which of the following antibiotics would routinely be tested and reported for isolates of
Pseudomonas aeruginosa?
a. penicillin
