ASCP Technologist in Microbiology 2

Question 1

Which staining technique is most commonly used to differentiate bacteria into two major groups?

Accepted Answer

Gram stain

Answer

The Gram stain classifies bacteria as gram-positive (purple/blue) or gram-negative (pink/red) based on cell wall structure.

Question 2

What is the purpose of blood agar in microbiology?

Accepted Answer

To detect hemolysis patterns that help identify bacterial species

Answer

Blood agar detects hemolysis patterns (alpha, beta, gamma) produced by bacteria, aiding identification.

Question 3

Which organism is the most common cause of urinary tract infections?

Accepted Answer

Escherichia coli

Answer

E. coli causes approximately 80% of uncomplicated UTIs due to virulence factors that allow adherence to uroepithelial cells.

Question 4

What is the purpose of an antibiotic susceptibility test?

Accepted Answer

To determine which antibiotics will effectively inhibit or kill the pathogen

Answer

AST determines the minimum inhibitory concentration (MIC) of antibiotics against a bacterial isolate, guiding treatment selection.

Question 5

Which culture medium is selective for gram-negative bacteria?

Accepted Answer

MacConkey agar

Answer

MacConkey agar inhibits gram-positive bacteria (using bile salts and crystal violet) and differentiates gram-negatives by lactose fermentation.

ASCP Phlebotomy Technician Exam Practice Test