Gram stain: positive Cell shape: bacillus Arrangement: single Oxygen requirements: Optimum growth temperature: 30° Other: these organisms are acid fast.
Habitat: soil, plants, animals
Pathogenicity: This is probably the only bacterium that grows in the peripheral nervous system as opposed to the central nervous system. It can also grow in skin cells. Causative agent of Hansen's disease (leprosy). Because of optimum temp., it shows a preference for the outer, cooler portions of the body. It has a very long generation time and is impossible to grow in culture. Leprosy occurs in two main forms "tuberculoid: or the "lepromatous" form which is also called progressive. The tuberculoid form is characterized by regions of the skin that have lost sensation. This form occurs in people with effective immune responses. The progressive form affects skin cells and disfiguring nodules form all over the body. The nose, face and hands are commonly affected. Death is usually a result of a secondary opportunistic infection.
Diagnosis:detection of acid fast organism in the fluids from a lit cut in a cool site, such as the earlobe.
Transmission: airborne; prolonged contact with exudate from lesions or from organisms shed in large numbers in nasal secretions. Not very contagious.
Treatment: The number of cases are increasing today. Currently 200 cases are reported in the U.S. per year. Millions of people suffer worldwide. Dapsone is used but if there is resistance, rifampin and clofazimine are used with it.
Mycobacterium leprae
