Microbiology BOC Questions With Complete Solutions

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 correct answer: d 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 correct answer: d 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 correct answer: a 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 correct answer: b 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 100C d. requires a source of ethylene oxide correct answer: a 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 correct answer: a 7. An aspirate 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 correct answer: d 8. The proper blood-to-broth ratio for blood cultures to reduce the antibacterial effect of serum in adults is: