Isolation of nontuberculous Mycobacteria from the environment of Buruli ulcer endemic communities in Ghana.
BACKGROUND: This study aimed to isolate nontuberculous mycobacterial species from environmental samples obtained from some selected communities in Ghana.
METHODS: To optimise decontamination, spiked environmental samples were used to evaluate four solutions and supplemented media after which the best decontaminating solution and media were used for the actual analysis. The obtained isolates were identified by specific genetic sequences including heat shock protein 65, IS2404, IS2606, rpoB and ketoreductase gene as needed.
RESULTS: Among the evaluated methods, decontamination by 1M NaOH followed by 5% oxalic acid gave the highest recovery of mycobacteria (50.0%) and the least contamination (15.6%). The cultivating medium that supported the highest recovery of mycobacteria was PANTA (34.4%), followed by isoniazid (28.1%) supplemented media. Among the 139 samples cultivated in the main analysis, 58 (41.7%) yielded mycobacterial growths and 70 (50.4%) had no growth; 11 (7.9%) had all inoculated tubes contaminated. A total of twenty-five different mycobacterial species were identified. Fifteen (60 %) of these were slow growers (e.g. M. ulcerans, M. avium, M. mantenii, M. malmoense) and 10 (40 %) were rapid growers (e.g. M. chelonae, M. fortuitum and M. abscessus). The occurrence of mycobacteria species in the various environmental samples analysed were: soil 16 (43.2 %), vegetation 14 (38.0 %), water 3 (8.0 %), moss 2 (5.4%), snail 1 (2.7 %) and fungi 1 (2.7 %).
CONCLUSION: This study is the first to report on the isolation of M. ulcerans and other medically relevant nontuberculous mycobacteria from different environmental sources in Ghana.
IMPORTANCE: Diseases caused by mycobacterial species other than those that causes tuberculosis and leprosy are increasing. The control is difficult because current understanding of the mode of spread and where these germs live in the environment is limited. At the same time, this information is needed to design preventive measures. Moreover, growing of these organisms from the environment is also difficult, as the culturing medium gets overgrown by other bacteria that also live in the environment such as soil and water. We decided to improve methods for growing these germs from the environmental sources such as soil and water towards understanding of important mycobacteria ecology.