Genus divided into 3 groups: Mycobacterium tuberculosis complex, Mycobacterium leprae and nontuberculous mycobacteria.
Aerobic rods that grow in straight or branching chains with a waxy cell wall with mycolic acid.
Mycobacterium tuberculosis is a small acid fast, obligate aerobe residing inside macrophages.
Complex cell wall that differs from gram positive and gram negative organisms.
Cell walls possess complex lipids, mycosides.
Mycolic acid residues occur on the external cell wall along with other membrane proteins and cross linkages of the peptidoglycan layer.
Acid fast on staining and weakly positive with Gram stain.
The cell wall is a virulence factor with resistance to common antibiotics.
Many pathogenic mycobacteria exist and the two most important members of the genus are M. tuberculosis and M. leprae.