Which of the following are AFB positive with 5% sulphuric acid

NEET SS
#1

Which of the following are AFB positive with 5% sulphuric acid -

    1. M. avium
    1. M. leprae
    1. M. tuberculosis
    1. Nocardia
    1. Rhodococcus

0 voters

exp:

M. leprae is less acid fast than M. tuberculosis. Hence 5% sulfuric acid instead of 20% is employed for decolourisation after staining with carbol fuschin.

ACID FAST STAINING

  • After staining with aniline dye, acid fast organisms resist decolourisation with acids.
  • Method most commonly used is modified Ziehl Neelsen.

Acid fastness depends upon

  1. Mycolic acid
  2. Integrity of cell wall