Disease caused by environmental mycobacteria

Abstract There are over 130 species of mycobacteria; species other than M. tuberculosis complex and M. leprae are collectively referred to as the non-tuberculous or environmental mycobacteria. Non-tuberculous mycobacteria are divided into two groups, the slow growers, and the rapid growers. The most common organisms causing human disease are the slow-growing species M. avium complex and M. kansasii and, less commonly, M. marinum, M. xenopi, M. simiae, M. malmoense, and M. ulcerans. The rapid growers that are human pathogens are M. abscessus, M. fortuitum, and M. chelonae. Transmission to humans is though inhalation, ingestion, or traumatic inoculation. The prevalence of non-tuberculous mycobacteria infections is likely to have been underestimated, and appears to be increasing in developed countries.