FREE Medical Laboratory Technician Clinical Microbiology Questions and Answers

Question 1

A medical laboratory technician performs a Gram stain on a positive blood culture bottle.
Microscopic examination reveals spherical bacteria arranged in grape-like clusters that stain purple.
Which of the following organisms is most suggested by this morphology?

Accepted Answer

Staphylococcus aureus

Answer

Streptococcus pyogenes

Answer

Neisseria meningitidis

Answer

Escherichia coli

Question 2

An MLT inoculates a urine specimen onto a culture medium that is designed to inhibit the growth of Gram-positive organisms while differentiating between bacteria that can and cannot ferment lactose. Lactose fermenters produce pink-to-red colonies on this medium. What is this type of agar called?

Accepted Answer

MacConkey agar

Answer

Blood agar

Answer

Chocolate agar

Answer

Mannitol salt agar

Question 3

A Gram-positive coccus isolated from a skin abscess is tested in the lab. The organism produces bubbles when a drop of hydrogen peroxide is added (catalase-positive) and causes rabbit plasma to clot (coagulase-positive). What is the most likely identification of this organism?

Accepted Answer

Staphylococcus aureus

Answer

Streptococcus pyogenes

Answer

Staphylococcus epidermidis

Answer

Enterococcus faecalis

Question 4

Which of the following best describes the principle of the Kirby-Bauer disk diffusion susceptibility test?

Accepted Answer

Antibiotic-impregnated disks are placed on an inoculated agar plate, and the diameter of the zone of growth inhibition is measured after incubation.

Answer

The minimum concentration of an antibiotic that kills a bacterium is determined by serial dilutions in broth.

Answer

The presence of specific resistance genes in the bacterial DNA is detected using molecular amplification techniques.

Answer

A colorimetric change indicates the metabolic activity of bacteria in the presence of an antibiotic.

Question 5

While examining a trichrome-stained stool smear for ova and parasites, a technologist identifies a cyst that is approximately 14 µm in diameter. It is spherical and contains three nuclei, each with a small, central karyosome. A chromatoidal bar with bluntly rounded ends is also observed. This morphology is most characteristic of which organism?

Accepted Answer

Entamoeba histolytica/dispar

Answer

Giardia lamblia

Answer

Entamoeba coli

Answer

Cryptosporidium parvum

Question 6

A patient presents with vulvovaginitis, and a culture of the vaginal discharge grows creamy, white colonies on Sabouraud dextrose agar. A wet mount prepared from a colony reveals oval-shaped budding cells and elongated structures that look like links of sausage, referred to as pseudohyphae. What is the most likely pathogen?

Accepted Answer

Candida albicans

Answer

Aspergillus fumigatus

Answer

Cryptococcus neoformans

Answer

Trichomonas vaginalis

A medical laboratory technician performs a Gram stain on a positive blood culture bottle.Microscopic examination reveals spherical bacteria arranged in grape-like clusters that stain purple.Which of the following organisms is most suggested by this morphology?

A medical laboratory technician performs a Gram stain on a positive blood culture bottle.
Microscopic examination reveals spherical bacteria arranged in grape-like clusters that stain purple.
Which of the following organisms is most suggested by this morphology?