Medical Laboratory Technician Exam FREE Medical Laboratory Technician Clinical Microbiology Questions and Answers 3

Question 1

A CSF Gram stain from a neonate reveals Gram-positive short rods. Which organism should be suspected and what confirmatory test is characteristic?

Accepted Answer

Listeria monocytogenes confirmed by tumbling motility at 25 degrees C

Answer

Corynebacterium diphtheriae confirmed by Elek test

Answer

Bacillus cereus confirmed by lecithinase production

Answer

Lactobacillus species confirmed by vancomycin resistance

Question 2

Which selective and differential medium is used to isolate Neisseria gonorrhoeae from specimens containing mixed flora?

Accepted Answer

Modified Thayer-Martin agar

Answer

Hektoen enteric agar

Answer

Mannitol salt agar

Answer

Lowenstein-Jensen medium

Question 3

An anaerobic blood culture grows Gram-positive rods that produce a double zone of hemolysis on blood agar. What is the most likely organism?

Accepted Answer

Clostridium perfringens

Answer

Clostridium tetani

Answer

Bacteroides fragilis

Answer

Actinomyces israelii

Question 4

A sputum culture from an immunocompromised patient grows a mucoid, non-lactose-fermenting Gram-negative rod that produces a grape-like odor and is oxidase-positive. Which organism is identified?

Accepted Answer

Pseudomonas aeruginosa

Answer

Acinetobacter baumannii

Answer

Stenotrophomonas maltophilia

Answer

Burkholderia cepacia

Question 5

Which fungal organism appears as large, broad-based budding yeast cells in a KOH preparation of lung tissue from a patient in the Ohio River Valley?

Accepted Answer

Blastomyces dermatitidis

Answer

Histoplasma capsulatum

Answer

Coccidioides immitis

Answer

Cryptococcus neoformans

Question 6

What is the primary purpose of performing an antimicrobial susceptibility test using the Kirby-Bauer disk diffusion method?

Accepted Answer

To determine if an organism is susceptible, intermediate, or resistant to specific antibiotics

Answer

To identify the minimum bactericidal concentration of an antibiotic

Answer

To detect beta-lactamase production in Gram-negative rods

Answer

To determine the serum bactericidal titer for endocarditis treatment