Occurrence of nontuberculous mycobacteria in some selected water sources in the central region of Ghana

Abstract

Nontuberculous mycobacteria (NTM) are common saprophytes found in the environment, specifically in soil and water. These mycobacteria have recently been reported to be implicated in opportunistic infections with increasing frequency, especially in immunocompromised individuals. This study aimed to find the occurrence of NTM in some selected water sources in the Central Region of Ghana using treated water from, and water sources employed by the Ghana Water Company Limited (GWCL) as the main medium for the study. Water samples were decontaminated with 4% NaOH solution and cultured on Löwenstein-Jensen (LJ) slants at 30oC and 37oC for the recovery of Acid-fast bacilli (AFB). Post-culture Ziehl-Neelsen microscopy was done to identify AFB from isolates. This was followed by categorization of isolates as NTM using the Capilia TB-Neo assay. The 360 bp fragment of the rpoB gene was amplified for 17 (30.9%) isolates categorized as NTM and amplified products were separately subjected to digestion with the restriction endonucleases MspI and HaeIII. Resulting fragments were compared with those in a standard algorithm and the NTM species identified were M. celatum, M. gordonae type II, M. simae. M. genavense and M. kansasii V strain. The results of this study suggest that the water sources investigated harboured NTM, which can pose a potential public health hazard especially to immunodeficient individuals.