|TEM micrograph of M. tuberculosis.|
Mycobacterium is a genus of bacteria, with about 100 species.The genus includes pathogens known to cause serious diseases in mammals, including tuberculosis (Mycobacterium tuberculosis) and leprosy (Mycobacterium leprae).
Mycobacteria can colonize their hosts without the hosts showing any adverse signs. Many people around the world have infections of M. tuberculosis without showing any signs of it.
Mycobacterial infections are difficult to treat. The organisms are tough due to their cell wall. In addition, they are naturally resistant to a number of antibiotics that disrupt cell-wall building, such as penicillin. With their unique cell wall, they can survive long exposure to acids, alkalis, detergents, oxidative bursts, lysis by complement, and many antibiotics.