Abstract

AbstractThe atypical mycobacteria are identified readily when appropriate attention is paid to growth rates, pigment formation, and temperature requirements. They are widely distributed in nature with approximately 40 million of our population having been exposed to them as indicated by skin testing surveys. Various disease patterns are produced—pulmonary infection, lymphadenitis, cutaneous involvement, and less commonly, others. Organisms from all four of Runyon's groups may produce cutaneous infection, but the majority are caused by Mycobacterium marinum, which usually produces a granulomatous verrucose lesion, but at times may simulate sporotrichosis. Group 2 and group 3 organisms rarely affect the skin. Group 4 organisms typically produce subcutaneous abscesses following injections or trauma. Most atypical organisms show some resistance to the major antituberculous drugs, and sensitivity testing is necessary to determine chemotherapeutic agents of choice.