Water and nontuberculous mycobacteria

The atypical mycobacteria or nontuberculous mycobacteria differ from tuberculous mycobacteria (M. tuberculosis, M. bovis, M. africanum) because most of them are ubiquitous and saprophytic. A few are considered potential human pathogens: M. avium, M. intracellulare, M. chelonae, M. kansasii, M. marinum, M. fortuituma and M. ulcerans. The immunological status of a person determines the advance of disease: disseminated or localizated (lung disease, lymphadenitis, skin or soft tissue involvement). Over the last decades the incidence of mycobacteriosis has increased in account of Sida. M. avium–M. intracellulare complex (MAC) are predominant species. In contrast to M. tuberculosis person-to-person transmission does not occur with nontuberculous mycobacteria. These bacteria are ubiquitous and may be found in the environment especially in water. It is difficult to isolate mycobacteria from nature thus published results certainly under estimate reality. Several studies indicated that the fluctuation in the occurrence of environmental mycobacteria was in relation to chemical and physical characteristics of the water: pH, ions concentration, temperature, organic matter. Among water species, scotochromogen M. gordonae or M. flavescens are the most common. Rapidly growing species M. fortuitum or M. chelonae are also common water contaminants. On account of their resistance to decontaminating agents they cause abscesses or postsurgical infections. M. marinum, isolated from aquariums or swimming pools, is the agent of inflammatory cutaneous nodules. M. kansasii, M. xenopi are especially found in drinking water distribution water, they are responsible for pulmonary diseases. The majority of human mycobacteriosis are due to species of the complex MAC which are isolated more frequently in warm water. Epidemiologic studies suggest that natural or drinking water are the principal source of human contamination. Recently results obtained using molecular biology techniques as pulsed field gel electrophoresis demonstrated a relation between environmental and human species. The eradication of nontuberculous in water is not possible so preventive measure could be a good strategy to limit mycobacteria.