Mycobacterium smegmatis is a fast-growing, usually non-pathogenic Mycobacterium widely used as a model system. It was originally isolated from human smegma. M.smegmatis mc(2)155 was isolated in 1990, and unlike other M.smegmatis can be easily transformed by electroporation. Mycobacteria have an unusual outer membrane approximately 8nm thick, despite being considered Gram-positive. The outer membrane and the mycolic acid-arabinoglactan-peptidoglycan polymer form the cell wall, which constitutes an efficient permeability barrier in conjunction with the cell inner membrane.

The second genome of this strain (dated 2007-2012) is a re-sequencing of some small regions of the genome but is not a de novo sequencing of the full genome. The group of O. Lecompte wanted to submit the sequence as a third part annotation, but Genbank considered it was a new sequence since some bases are different from the initial TIGR sequence. UniProtKB has decided to give it the status of Complete proteome as it is based on the original TIGR sequence.