<unk>  is an acid-fast bacterial species in the phylum Actinobacteria and the genus Mycobacterium.  It is 3.0 to 5.0 µm long with a bacillus shape and can be stained by Ziehl-Neelsen method and the auramine-rhodamine fluorescent method. It was first reported in November 1884 by Lustgarten, who found a bacillus with the staining appearance of tubercle bacilli in syphilitic chancres.  Subsequent to this, Alvarez and Tavel found organisms similar to that described by Lustgarten as well as in normal genital secretions (smegma). This organism was later named<unk> .
Mycobacterium smegmatis
Bacillus anthracis
Mycobacterium terrae
Mycobacterium tuberculosis
Mycobacterium avium intracellulare
Mycobacterium marinum
Mycobacterium xenopi
Mycobacterium avium complex