Identification of potentially pathogenic Nontuberculous mycobacteria isolated from drinking water systems in Tehran

Aim and Nontuberculous mycobacteria (NTM) are widely dispersed in the environment and are commonly isolated from environmental sources. Several species of environmental mycobacteria have been known to be important as human pathogens. The aim of this study was the isolation and molecular identification of NTM recovered from Tehran drinking water samples. From 22 different municipality regions of Tehran, 44 water samples were collected and passed through 0.45 μm filters. Filters were rinsed, treated with NaOH and SDS and transferred onto Lowenstein-Jensen medium. The isolates were subjected for molecular identification by sequencing rpoB gene. All of the collected waster samples were positive for NTM. Three samples had two types of NTM while the rest had one NTM isolate in pure culture. Contamination rate was 1%. Total of 47 isolates were isolated. Using rpoB gene sequencing M. simiea, M. fortuitum and M. gordonae were most frequent encountered species. Our findings showed NTM are the most common inhabitant bacteria in drinking water systems. This study provided impotent evidence about distribution of NTM in environmental sources.