1.1 Characteristics of Mycobacterium tuberculosis bacillus

Mycobacterium tuberculosis (variant tuberculosis), along with other variants (e.g. bovis, africanum, microti), make up the Mycobacterium tuberculosis complex, a group of bacteria that cause clinical tuberculosis (TB) in humans [1] Citation 1. Riojas MA, McGough KJ, Rider-Riojas CJ, Rastogi N, Hazbón MH. Phylogenomic analysis of the species of the Mycobacterium tuberculosis complex demonstrates that Mycobacterium africanum, Mycobacterium bovis, Mycobacterium caprae, Mycobacterium microti and Mycobacterium pinnipedii are later heterotypic synonyms of Mycobacterium tuberculosis. Int J Syst Evol Microbiol. 2018 Jan;68(1):324-332.
https://doi.org/10.1099/ijsem.0.002507 .

Most TB cases are caused by M. tuberculosis variant tuberculosis. Cases due to other variants are less prevalent.

M. tuberculosis is a small, rod-shaped, strictly aerobic, acid-fast bacillus a Citation a. Acid-fast bacilli (AFB) are bacilli, which once stained, resist discoloration by acid and alcohol. . Like other mycobacteria, it is slow growing, resulting in a slower development of disease when compared with other bacterial infections.