RMA Microbiology and Specimen Collection 3

Question 1

Which staining method is used to differentiate bacteria into gram-positive and gram-negative groups?

Accepted Answer

Gram stain

Answer

The Gram stain separates bacteria by cell wall characteristics into gram-positive (purple) and gram-negative (pink/red).

Question 2

What color do gram-positive bacteria appear after Gram staining?

Accepted Answer

Purple/blue

Answer

Gram-positive bacteria retain the crystal violet stain and appear purple/blue.

Question 3

A specimen for anaerobic culture should be handled how?

Accepted Answer

Transported quickly with minimal air exposure

Answer

Anaerobic organisms die when exposed to oxygen, so specimens must be transported quickly with minimal air exposure.

Question 4

Which stain is specifically used to identify Mycobacterium tuberculosis?

Accepted Answer

Acid-fast (Ziehl-Neelsen) stain

Answer

The acid-fast stain detects mycobacteria, which resist decolorization due to their waxy cell wall.

Question 5

What is the minimum recommended volume for an adult blood culture per bottle to maximize pathogen detection?

Accepted Answer

8-10 mL

Answer

Filling each bottle with 8-10 mL of blood optimizes the sensitivity of blood culture detection in adults.

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