Which of the following stains is also known as acid fast stain?

Appeared in: UPRVUNL - 2021

Explanation

Ziehl-Neelsen (ZN) staining is the specific method commonly referred to as the acid-fast stain.
This technique is crucial for identifying acid-fast bacilli (AFB), with Mycobacterium tuberculosis (the causative agent of tuberculosis) being the most prominent example.
The principle relies on the unique, waxy mycolic acid in the cell wall of mycobacteria, which resists decolorization by acid-alcohol after staining with a potent dye like carbol fuchsin.

Option A: Albert stain is a differential stain used specifically to demonstrate metachromatic granules (volutin granules) in Corynebacterium diphtheriae, the bacterium that causes diphtheria.
Option B: This is incorrect. Joseph Lister is a historical figure renowned for his pioneering work in antiseptic surgery, not for developing a specific staining method known as 'Lister stain'.
Option C: This is incorrect. Louis Pasteur is one of the fathers of microbiology, but the acid-fast stain is not named after him.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Synonyms and applications of microbiological staining techniques as background academic context rather than a clinical decision trigger.
The ZN stain is a fundamental, rapid, and cost-effective diagnostic tool for tuberculosis (TB), a major public health concern, especially in India.
Nurses are often responsible for collecting appropriate sputum samples from patients suspected of having pulmonary TB, ensuring a good quality specimen (purulent part, not just saliva) for accurate lab results.
What if? If a Gram stain were performed on a sputum sample from a patient with tuberculosis, the Mycobacterium would likely not stain or stain poorly (appearing as 'ghost cells') because the waxy cell wall prevents the Gram stain dyes from penetrating effectively. This highlights the need to use the correct stain based on the suspected pathogen.

How to Approach the Question

This is a factual recall question testing knowledge of microbiology terminology.
First, identify the key term in the question: 'acid fast stain'.
The question asks for a synonym ('also known as').
Recall or deduce the specific name for the acid-fast staining procedure from your microbiology studies.
Evaluate the options: Albert stain is for diphtheria; Lister and Pasteur are famous scientists but not associated with this specific stain name.
Conclude that Ziehl-Neelsen staining is the correct synonym for the acid-fast stain.

Concept Tested & Keywords

Concept Tested: Synonyms and applications of microbiological staining techniques.
Stem keywords: stain, acid fast stain
Lead-in keywords: also known as
Negative lead-in flag: false

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E6 Microbiology Essentials Sastry 4e Part 1 p. 46-48

E6 Microbiology Applied AnjuDhir 3e Part 1 p. 109-111

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