Microbiology & Parasitology

26 Questions | Total Attempts: 444

SettingsSettingsSettings
Please wait...
Microbiology Quizzes & Trivia

Registry study questions


Questions and Answers
  • 1. 
    Proper media for culture of a urethral discharge from a man include:
    • A. 

      Sheep blood and phenylethyl alcohol agars

    • B. 

      Eosin-methylene blue and sheep blood agars

    • C. 

      Thioglycollate broth and chocolate agar

    • D. 

      Chocolate and modified Thayer-Martin agars

  • 2. 
    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?
    • A. 

      70

    • B. 

      700

    • C. 

      7,000

    • D. 

      70,000

  • 3. 
    The lowest concentration of antibiotic that inhibits growth of a test organism is the:
    • A. 

      Minimum inhibitory concentration

    • B. 

      Serum inhibitory concentration

    • C. 

      Minimum bactericidal titer

    • D. 

      Maximum inhibitory titer

  • 4. 
    Which of the following clean catch urine culture colony counts indicates the patient likely has a urinary tract infection?
    • A. 

      10^1 CFU/mL

    • B. 

      10^3 CFU/mL

    • C. 

      10^5 CFU/mL

    • D. 

      No growth

  • 5. 
    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 100 degrees C

    • D. 

      Requires a source of ethylene oxide

  • 6. 
    The expected colony count in a suprapubic urine from a healthy individual is:
    • A. 

      0 CFU/mL

    • B. 

      100 CFU/mL

    • C. 

      1,000 CFU/mL

    • D. 

      100,000 CFU/mL

  • 7. 
    An aspiration of a deep wound was plated on blood agar plates and incubated aerobically and anaerobically. At 24 hours there was growth on both plates. This indicates that the organism is a(n):
    • A. 

      Nonfermenter

    • B. 

      Obligate anaerobe

    • C. 

      Aerobe

    • D. 

      Facultative anaerobe

  • 8. 
    The proper blood-to-broth ration for blood cultures to reduce the antibacterial effect of serum in adults is:
    • A. 

      1:2

    • B. 

      1:3

    • C. 

      1:10

    • D. 

      1:30

  • 9. 
    A penicillin-resistant Neisseria gonorrhoeae produces:
    • A. 

      Alpha-hemolysin

    • B. 

      Beta-lactamase

    • C. 

      Enterotoxin

    • D. 

      Coagulase

  • 10. 
    Which selective medium is used for the isolation of gram-positive microorganisms?
    • A. 

      Columbia CNA with 5% sheep blood

    • B. 

      Trypticase soy agar with 5% sheep blood

    • C. 

      Eosin methylene blue

    • D. 

      Modified Thayer-Martin

  • 11. 
    The most sensitive substrate for the detection of beta-lactamases is:
    • A. 

      Penicillin

    • B. 

      Ampicillin

    • C. 

      Cefoxitin

    • D. 

      Nitrocefin

  • 12. 
    A Stephylococcus aureus isolate has an MIC of 4ug/mL to oxacillin. There is uncertainty as to whether this represents an oxacillin (heteroresistant) resistant strain or a hyperproducer of beta lactamase. Strain                             Oxacillin                  Amoxicillin-clavulanic acid strain A                            s                              s strain B                            s                              r strain C                            r                              s strain D                            r                              r Based on the above results for oxacillin and amoxicillin-clavulanic acid, which strain is heteroresistant?
    • A. 

      Strain A

    • B. 

      Strain B

    • C. 

      Strain C

    • D. 

      Strain D

  • 13. 
    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

  • 14. 
    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. 

      Dept of agar

  • 15. 
    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 degrees C

    • C. 

      Incubation for 48 hours

    • D. 

      Use of cefoxitin for testing

  • 16. 
    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 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 slant with positive and negative controls for H2S production

    • D. 

      Verify reactivity of phenylalanine deaminase with postive and negative controls

  • 17. 
    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 previouly 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 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

  • 18. 
    Three sets of blood cultures were obtained from an adult patient with fever and suspected endocarditis. The aerobic bottle of one set had growth of Staphylococcus epidermidis at 5 days of incubation. This indicates that:
    • A. 

      There was a low-grade bacteremia

    • B. 

      The organism is most likely a contaminant

    • C. 

      The patient has a line infection

    • D. 

      The blood culture bottles are defective

  • 19. 
    In order to isolate Campylobacter coli/jejuni, the fecal specimen should be:
    • A. 

      Inoculated onto selective plating media and incubated in reduced oxygen with added CO2 at 42 degrees C

    • B. 

      Stored in tryptic soy brother before plating to ensure growth of the organism

    • C. 

      Inoculated onto selective plating media and incubated at both 35 degrees and at room temperature

    • D. 

      Incubated at 35 degrees C for 2 hours in Cary-Blair media before inoculating onto selective plating media

  • 20. 
    An expectorated sputum is sent to the laboratory for culture from a patient with respiratory distress. The gram stain of the specimen shows many squamous epithelial cells (>25/lpf) and rare neutrophils. The microscopic appearance of the organism presents include:
    • moderate gram-positive cocci and chains and diplococci
    • moderate gram-negative diplococci
    • moderate palisading gram-positive bacilli all in moderate amounts
    This gram stain is most indicative of:
    • A. 

      A pneumococcal pneumonia

    • B. 

      An anaerobic infection

    • C. 

      An Haemophilus pneumonia

    • D. 

      Oropharyngeal flora

  • 21. 
    Which type of microscope would be most useful in examining viruses and the structure of microbial cells?
    • A. 

      Electron

    • B. 

      Phase-contrast

    • C. 

      Dark-field

    • D. 

      Bright-field

  • 22. 
    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

  • 23. 
    In disk diffusion susceptibility testing, as an antibicrobial agent diffuses away from the disk, the concentration of antibiotics:
    • A. 

      Increased

    • B. 

      Decreased

    • C. 

      Unchanged

    • D. 

      Inoculum dependent

  • 24. 
    The most common cause for failure of a gaspak anaerobic jar to establlish an adequate environment for anaerobic incubation is:
    • A. 

      The failure of the oxidation-reduction potential indicator system due to deterioration of methylene blue

    • B. 

      The failure of the packet to generate adequate H2 and/or CO2

    • C. 

      Condensation of water on the inner surface of the jar

    • D. 

      Catalysts that have become inactivated after repeated use

  • 25. 
    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 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

Back to Top Back to top