Acid-Fast Staining and Tuberculosis Diagnosis

Flashcards covering the Ziehl-Neelsen staining technique, acid-fast organisms, and tuberculosis diagnostic methods and treatments.

Ziehl-Neelsen Technique

A staining procedure involving Kinyoun's carbol fuchsin for $5$ minutes, decolorization with $3\%$ acid alcohol for $3$ minutes, and counterstaining with Methylene blue for $1$ minute.

Acid fastness

A physical property that gives an organism the ability to resist decolorization by acids during staining procedures.

Mycolic acid

A high molecular weight long-chain fatty acid layer found in the cell wall of acid fast bacilli that acts as a barrier preventing primary stain removal.

Mycobacterium tuberculosis (Hot method)

Bacterial species requiring $25\%$ Sulfuric acid for decolorization.

Mycobacterium tuberculosis (Cold method)

Bacterial species decolorized using $3\%$ acid alcohol, also known as Kinyoun’s method.

Mycobacterium leprae

Bacterial species that is more easily decolorized due to its thinner cell wall; it requires $5\%$ sulfuric acid.

Nocardia

An acid-fast organism requiring $1\%$ Sulfuric acid for decolorization.

Bacterial spore decolorization

Requires a Sulfuric acid concentration of $0.25-0.5\%$.

Hooklets of Taenia saginata

A parasite structure requiring $1\%$ Sulfuric acid for decolorization.

Cryptosporidium, Cyclospora, and Cystoisospora

Parasites that require $1\%$ Sulfuric acid for decolorization.

Glia

A lipid-like substance that binds Lepra bacilli together, facilitating characteristic clumping behavior.

Globi

The term for cigar-like bundles or groups in which M. leprae are arranged.

NTEP sputum guidelines

Requires a minimum of $2$ sputum samples from a patient: a spot sample and an early morning sample.

Modified Petroff’s method

A technique used for sputum concentration.

Grading of M. tuberculosis

A process used to quantify bacterial load, monitor treatment response, assess disease severity, and determine infectiousness.

Auramine-rhodamine fluorescent staining

An alternative staining method for demonstrating M. tuberculosis designed to be viewed under a fluorescence microscope.

Lowenstein-Jensen (LJ) medium

A selective culture media used for isolating M. tuberculosis, typically requiring an incubation of four weeks.

PPD

Acronym for purified protein derivative, used in skin tests to detect tuberculosis bacteria.

Mantoux test

A test to determine TB infection by injecting a small amount of PPD from a dead TB bacillus; a reaction at the site indicates possible infection.

First Line ATT Drugs

A classification of anti-tuberculosis treatment including Rifampicin, Isoniazid, Pyrazinamide, and Ethambutol.

Second Line ATT Drugs

A classification including Kanamycin, Streptomycin, Amikacin, Levofloxacin, Moxifloxacin, and Gatifloxacin.

MDR TB

Multi-drug resistant tuberculosis infection that is resistant to at least two of the first line anti-TB drugs.

XDR TB

Extensively drug-resistant TB strains that are resistant to fluoroquinolones and second line injectable drugs.

Kinyoun’s method (Cold method)

An acid-fast staining method characterized by using $3\%$ acid alcohol as a decolorizer and a higher phenol concentration in its carbol fuchsin compared to the hot method.