The rapidly growing mycobacteria--Mycobacterium fortuitum and Mycobacterium chelonei.

In summary, rapidly growing mycobacteria, M. fortuitum and M. chelonei, are pathogens of increasing importance which are often hospital-acquired and can infect patients with iatrogenic immunosuppression. They readily grow on routine mycobacterial culture media and must be distinguished from non-pathogenic rapidly growing species and slowly growing mycobacteria. Widely distributed in nature, they are often present in hospital environments, especially in water. Compared to M. tuberculosis they are weak pathogens, and infected patients are not considered contagious. Disease is probably acquired from environmental sources by direct entry of the organisms through traumatized skin or mucous membranes or by aspiration into previously abnormal lungs. They are usually resistant to antituberculous agents but are susceptible to several commonly used antibacterial agents. Treatment generally requires one or more active antibiotics plus adjunctive surgery in many cases. Prevention of nosocomial infection lies in proper disinfection of potentially contaminated medical devices and elimination of contaminated water.