Tuberculosis and Other Mycobacteria

The genus Mycobacterium is one of the most widely distributed bacteria genera in nature and includes those organisms that cause two of the world's most prevalent infectious diseases in humans, M. tuberculosis, the agent of tuberculosis and M. leprae, the agent of leprosy. A large number of other species in this genera are widespread and occur as contaminants in soil, water, or organic debris. These organisms may be ingested or inhaled in dust particles and produce syndromes that are indistinguishable from classic tuberculosis. The term tuberculosis (TB) is commonly applied to all cases of mycobacterial infections except leprosy. Many of these infections are now being recognized more frequently in immunosuppressed patients who have organ transplants, individuals being treated for leukemia or cancer, and patients suffering from AIDS. In most cases of TB in humans, the lungs are the major organ affected but other tissues and organs such as bone, skin, and the digestive tract may also be infected. Although this chapter focuses primarily on tuberculosis, a discussion of a few of these other opportunistic organisms in this genus that are associated with human disease are also discussed. The bibliography provided will guide the readers to works which they can consult for more detailed information about these organisms. These references contain discussions on taxonomy, growth requirements, as well as the morphological characteristics, physiology, pathogenicity, and the metabolic activity of these organisms. Keywords: Tuberculosis; Organisms; Sources; Health issues; Risk factors; Prevention; Treatment