Microbiology I and II Multiple Choice Questions
1.
If a human develops cysticercosis, by which means was the infection transmitted? (a) (b) (c) (d) (e)
2.
Which infection predisposes to bladder cancer? (a) (b) (c) (d)
3.
Eating beef Eating pork Fecal oral from pig feces Fecal oral from cow feces Fecal oral from human feces
Schistosoma haematobium Schistosoma mansoni Schistosoma japonicum Clonorchis sinensis
A healthy, non-pregnant, college-aged female complains of dysuria and urinary frequency. A urine dipstick shows 2+ leukocyte esterase, esterase, with a negative nitrite. nitrite. A urine sediment shows 50 WBC and few bacteria. How should a urine culture report of rare 2 (10 ) Staph. saprophyticus in her urine be interpreted? (a) There are too few organisms in the urine culture to represent represent significant bacteruria; the patient does not have a UTI. (b) Taking the findings together, there is adequate evidence of a UTI. (c) The findings are inconclusive. Another urine culture should be sent. (d) The findings are inconclusive. Another urine dipstick should be sent.
4.
Neisseria gonorrhoeae is able to ferment which of the following carbohydrates:
(a) (b) (c) (d) 5.
Which species of Shigella is most prominent in the US? (a) (b) (c) (d)
6.
Glucose only Glucose and maltose Glucose, maltose, maltose, and sucrose Glucose, maltose, sucrose, and lactose
S. dysenteriae (serogroup A) S. flexneri (serogroup B) S. boydii (serogroup C) S. sonnei (serogroup D)
Which species of Shigella is associated with the hemolytic-uremic syndrome? (a) (b) (c) (d)
S. dysenteriae (serogroup A) S. flexneri (serogroup B) S. boydii (serogroup C) S. sonnei (serogroup D)
7.
Which is true of E. coli O157:H7? (a) (b) (c) (d)
8.
RNA testing in HCV infection can be used to: (a) (b) (c) (d)
9.
Bacitracin susceptibility test Optochin susceptibility test Novobiocin susceptibility test Vancomycin susceptibility test
Why won’t H. influenzae grow on sheep blood agar? (a) (b) (c) (d)
11.
Predict response to therapy Assess response to therapy Confirm the presence of HCV infection All of the above
Which of the following is a test used to differentiate between Streptococcus pneumoniae and viridans streptococci? (a) (b) (c) (d)
10.
Ferments sorbitol Does not ferment sorbitol Does not ferment glucose Shows fluorescence when grown on MUG-containing media
Sheep blood cells produce neither X factor nor V factor Sheep blood cells produce only X factor Sheep blood cells produce only V factor Sheep blood cells produce both X and V factors, but an enzyme present in the blood hydrolyzes the V factor
A primary gram stain shows filamentous, branching gram positive rods. A modified acid fast stain from the same specimen reveals that the bacteria are modified acid fast positive. The organism is most likely to be which of the following: (a) Actinomyces (b) Streptomyces (c) Nocardia (d) Mycobacterium tuberculosis
12.
A lung biopsy shows an invasive fungal pneumonia. Morphologically, the organism has relatively narrow, regularly septated, hyaline hyphae, with acute angle branching. Although you suspect Aspergillus, which of the following cannot be ruled out? (a) Mucor (b) Coccidioides immitis (c) Pseudallescheria boydii/Scedosporium apiospermum (d) Rhizopus
13.
Which of the following dimorphic fungi produces a diffusible red pigment when grown on standard culture media? (a) Histoplasma capsulatum (b) Penicillium marneffei (c) Blastomyces dermatitidis (d) Paracoccidiodes brasiliensis
14.
A 9 year old child visits her primary care physician with signs and symptoms of pertussis (whooping cough). The patient’s cough began 20 days prior to this visit. The child’s mother is fairly certain that the patient was properly vaccinated. In order to confirm the diagnosis, the clinician should: (a) (b) (c) (d)
15.
When a mycobacterium is described as a scotochromogen, this means that colonies of the organism on solid media are: (a) (b) (c) (d)
16.
Preference for a keratin-rich environment Cause infection in both healthy and immunocompromised patients Hyphae are darkly pigmented Able to grow in the presence of cycloheximide
All of the following are characteristics of rapid growing mycobacteria except:
(a) (b) (c) (d) 18.
Non-pigmented whether grown in dark or light Pigmented whether grown in dark or light Non-pigmented when grown in the dark, but pigmented after exposure to light Pigmented when grown in the dark, but the pigment disappears after exposure to light
All of the following are characteristics of dermatophytes except:
(a) (b) (c) (d) 17.
Send a nasopharyngeal aspirate or swab for B. pertussis culture Send blood for B. pertussis serology Send for both culture and serology Do nothing—no workup is indicated
Positive for arylsulfatase activity in 3 days Non-pigmented Cell wall lacks mycolic acids Growth on MacConkey agar lacking crystal violet
Trichomonas vaginalis is an example of which type of protozoa:
(a) (b) (c) (d)
Amoeba Flagellate Ciliate Sporozoan
19.
A 20 year old pregnant female is screened for HIV using the ELISA method. The ELISA is positive, so a Western blot is run for confirmation. The Western blot is negative. The correct interpretation of these findings is: (a) The Western blot result is a false negative. The patient is infected with HIV. (b) The ELISA result is a false positive. The patient is not infected with HIV. (c) The results are indeterminant. The ELISA should be repeated after a few months. (d) The results are indeterminant. The Western blot should be repeated after a few months.
20.
An 18 year old male presents to his primary care physician with a sore throat, a fever of 100.5 F, and enlarged submandibular lymph nodes. The clinician realizes that acute EBV infection is in the differential diagnosis, and orders a heterophile antibody test. The test is negative. The correct interpretation of these findings is: (a) The patient does not have acute EBV. (b) The patient does have acute EBV. (c) The negative test cannot rule out acute EBV infection. The heterophile antibody test should be repeated after a few weeks. (d) The negative test cannot rule out acute EBV infection. There is no point in repeating the heterophile antibody test, because if it is negative the first time, it will always be negative.
21.
A 65 year old female is recovering from a lung transplant in the hospital. She has a 2week old central line. She develops a fever, and blood cultures are sent. Three of four blood culture bottles are positive for Candida glabrata. The intern taking care of her suggests treating her with fluconazole. The attending physician should: (a) Agree with the intern and treat with fluconazole. Fluconazole is nearly always active against Candida glabrata. (b) Disagree with the intern and treat with another antifungal agent (e.g. Amphotericin B). A significant proportion of Candida glabrata isolates from blood are fluconazole resistant. (c) Disagree with the intern and treat with another antifungal agent (e.g. Amphotericin B). Candida glabrata is always resistant to fluconazole. (d) Disagree with the intern. Fluconazole is never used to treat Candidemia.
22.
A 54 year old male has a history of a mitral valve replacement 18 months prior to admission. He presented to the emergency room with fever and chills, 2 days after he saw his dentist for a root canal. He says he did not take prophylactic antibiotics prior to the procedure, but did take them the next day. Blood culture are drawn, and 2/4 bottles are positive for gram positive cocci in chains. The blood cultures are subcultured to sheep blood agar with an optochin disk. Growth on the plate shows which alphahemolytic colonies that are resistant to optochin. A catalase test is negative. The bile esculin test is positive, but the PYR test is neg ative, and the isolate cannot grow in the presence of 6.5% NaCl. The correct identification of this organism is: (a) Streptococcus pyogenes (b) Streptococcus pneumoniae (c) Viridans streptococcus (d) Streptococcus bovis
Answers: for Microbiology I & II – John Branda, MD
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22.
E A B A D A B D B D C C B A B C C B D C. B D
