Mycobacteria are small, slow-growing, aerobic bacilli distinguished by a complex, lipid-rich cell envelope responsible for their characterization as acid-fast (ie, resistant to decolorization by acid after staining with carbolfuchsin) and their imperviousness to Gram stain. The most common mycobacterial infection is tuberculosis; others include leprosy and various diseases caused by Mycobacterium avium complex.

Last full review/revision September 2009 by Edward A. Nardell, MD