The bacterial genus
Mycobacterium
contains more than 120 members, several of which are extremely successful pathogens of man and animals including the agents of tuberculosis and leprosy. All mycobacteria are aerobic, nonmotile, nonspore forming, Gram‐positive bacteria with a high genomic guanine + cytosine (GC) content. They possess a thick cell wall that contains unique lipids, called mycolic acids, which confer a characteristic acid‐fast staining property and make the genus hardy and resistant to antimicrobials and host defences.