Ziehl-Neelsen staining, culture in Lowenstein-Jensen medium and GeneXpert MTB/RIF assay are useful methods for the diagnosis of tuberculosis.
M. tuberculosis gives rough, raised, dry, non-pigmented (cream/buff colored) colonies on Lowenstein Jensen (LJ) medium.
GeneXpert MTB/RIF assay is a NAAT that simultaneously detects DNA of M.tuberculosis complex and resistance to rifampin (i.e. mutation of the rpoB gene).
Tuberculin skin test is the standard method of determining whether a person is infected with M.tuberculosis or has exposure to tubercle bacilli.
Mycobacterium species possess an enzyme-lipase, that splits Tween-80 and releases oleic acid and polyoxyethylated sorbitol.
Atypical mycobacteria include species such as M. avium, M. intracellularae, M. kansasii, M. xenopi, and M. fortuitum.
Ziehl-Neelsen acid fast stain is designed to stain bacterial cells containing long chain fatty (mycolid acids) such as Mycobacterium.
Sodium hypochlorite centrifugation technique is used to concentrate the AFB present in the sputum, as it increases the chances of detecting AFB.
Tests are; Tween-80 hydrolysis test, niacin test, nitrate reduction test, tellurite reduction test, urea hydrolysis test and citrate utilization test.