BOC: MICROBIOLOGY EXAM 3 QUESTIONS
WITH 100 CORRECT ANSWERS [ GRADED
A+]
>100,000 CFU/mL of a gram-negative bacilli were isolated on MacConkey from a
urine specimen. Biochemical results are as follows:
Glucose: acid, gas produced
Indole: negative
Urea: positive
TDA: positive
H₂S: positive
©morren2024/2025.Year published 2024.
,The organism is most likely:
Morganella morganii
Proteus mirabilis
Proteus vulgaris
Providencia stuartii - ✔✔Proteus mirabilis
Susceptibility tsting is performed on a Staphylococcus aureus isolate from a blood
culture with the following results:
Oxacillin: Resisitant
Cefazolin: Susceptible
Clindamycin: Susceptible
Erythromycin: Susceptible
Trimethoprim/Sulfamethoxazole: Susceptible
Vancomycin: Susceptible
©morren2024/2025.Year published 2024.
,What should the technologist do next?
Ceftraixone should be reported instead of cefazolin
Clindamycin should be tested for inducible resistance prior to reporting
The trimethoprim/sulfamethoxazole result should be removed since all S aureus
are resistant
The cefazolin result should be changed to resistant since the oxacillin result is
resistant - ✔✔The cefazolin result should be changed to resistant since the
oxacillin result is resistant
Proper media for culture of a urethral discharge from a man:
Sheep blood and phenyl ethyl alcohol agars
Eosin-methylene blue and sheep blood agars
Thioglycollate broth and chocolate agar
©morren2024/2025.Year published 2024.
, Chocolate and modified Thayer-Martin agars - ✔✔Chocolate and modified
Thayer-Martin agars
A sheep blood agar plate inoculated with 0.001 mL of urine grows 70 colonies of
Staphylococcus aureus. How many colony forming units per mL of urine should be
reported?
70
700
7,000
70,000 - ✔✔70,000
The lowest concentration of antibiotic that inhibits growth of a test organism:
Minimum inhibitory concentration
Serum inhibitory concentration
©morren2024/2025.Year published 2024.
WITH 100 CORRECT ANSWERS [ GRADED
A+]
>100,000 CFU/mL of a gram-negative bacilli were isolated on MacConkey from a
urine specimen. Biochemical results are as follows:
Glucose: acid, gas produced
Indole: negative
Urea: positive
TDA: positive
H₂S: positive
©morren2024/2025.Year published 2024.
,The organism is most likely:
Morganella morganii
Proteus mirabilis
Proteus vulgaris
Providencia stuartii - ✔✔Proteus mirabilis
Susceptibility tsting is performed on a Staphylococcus aureus isolate from a blood
culture with the following results:
Oxacillin: Resisitant
Cefazolin: Susceptible
Clindamycin: Susceptible
Erythromycin: Susceptible
Trimethoprim/Sulfamethoxazole: Susceptible
Vancomycin: Susceptible
©morren2024/2025.Year published 2024.
,What should the technologist do next?
Ceftraixone should be reported instead of cefazolin
Clindamycin should be tested for inducible resistance prior to reporting
The trimethoprim/sulfamethoxazole result should be removed since all S aureus
are resistant
The cefazolin result should be changed to resistant since the oxacillin result is
resistant - ✔✔The cefazolin result should be changed to resistant since the
oxacillin result is resistant
Proper media for culture of a urethral discharge from a man:
Sheep blood and phenyl ethyl alcohol agars
Eosin-methylene blue and sheep blood agars
Thioglycollate broth and chocolate agar
©morren2024/2025.Year published 2024.
, Chocolate and modified Thayer-Martin agars - ✔✔Chocolate and modified
Thayer-Martin agars
A sheep blood agar plate inoculated with 0.001 mL of urine grows 70 colonies of
Staphylococcus aureus. How many colony forming units per mL of urine should be
reported?
70
700
7,000
70,000 - ✔✔70,000
The lowest concentration of antibiotic that inhibits growth of a test organism:
Minimum inhibitory concentration
Serum inhibitory concentration
©morren2024/2025.Year published 2024.
