Question

Which staining technique is used specifically to identify Mycobacterium tuberculosis?

• A. Gram Staining
• B. Acid-fast Staining
• C. Capsule Staining
• D. Endospore Staining

Hint:

Mycobacterium → Acid-fast → Ziehl–Neelsen staining → Red cells.

Answer 1

The Correct Option is B

Concept: Different microorganisms require specific staining techniques based on their cell wall composition. Mycobacterium tuberculosis has a unique waxy cell wall rich in mycolic acids.
Step 1: Understanding Acid-fast property.
Due to the presence of mycolic acids, the bacteria resist decolorization by acid-alcohol after staining.
Step 2: Staining technique used.
Acid-fast staining (Ziehl–Neelsen staining) is specifically used to identify such bacteria.
Step 3: Procedure insight.

• Primary stain: Carbol fuchsin
• Decolorizer: Acid-alcohol
• Counterstain: Methylene blue

Acid-fast bacteria appear red, while non-acid-fast bacteria appear blue.
Step 4: Eliminating other options.

• Gram staining: Not effective due to waxy cell wall
• Capsule staining: Identifies capsules
• Endospore staining: Detects spores

Step 5: Conclusion.
Thus, Acid-fast staining is used to identify Mycobacterium tuberculosis.