What is the role of nalc in concentration procedure for mycobacteria

N-acetyl-L-cysteine (NALC) is a crucial reagent used in the decontamination and concentration of specimens, especially respiratory samples such as sputum, for the detection of Mycobacterium tuberculosis. It performs a specific function that greatly enhances the efficiency and sensitivity of the diagnostic process.

1. Serves as a Mucolytic Agent

• NALC breaks down mucus by cleaving disulfide bonds in mucoproteins, thereby liquefying the thick, viscous components of sputum.
• This mucolysis is essential to release any trapped mycobacteria, making them available for further processing.

2. Facilitates Uniform Decontamination

• By liquefying the sample, NALC allows the decontaminating agents like sodium hydroxide (NaOH) to act uniformly throughout the specimen.
• This ensures that contaminating flora are efficiently removed without excessive destruction of mycobacteria.

3. Enhances Recovery of Mycobacteria

• Liquefied samples allow better sedimentation during centrifugation, concentrating the bacilli into the pellet.
• The result is a higher diagnostic yield in smear microscopy and culture, especially in paucibacillary specimens.

4. Functions Rapidly and Synergistically

• NALC works synergistically with NaOH for decontamination but has a short half-life; thus, it must be used immediately after preparation.
• The fast action allows quick sample processing without prolonged exposure to harsh chemicals.