Mycobacterium

Mycobacterium is a genus of Gram-positive bacilli that demonstrate the staining
characteristic of acid-fastness. Its most important species, Mycobacterium tuberculosis, is the etiologic agent of tuberculosis, the “consumption” referred to above. One of the oldest and most devastating of human afflictions, tuberculosis remains a leading cause of infectious disease deaths worldwide today. A second mycobacterium, Mycobacterium leprae,is the causative agent of leprosy. A large number of less pathogenic species collectively referred to as “atypical mycobacteria” or “nontuberculous mycobacteria,” are assuming increasing importance as disease agents in immunocompromised patients, particularly those with acquired immunodeficiency syndrome (AIDS).