Isolation of Environmental Mycobacteria from Diverse Water Samples Using Cetylpyridinium Chloride

Despite of the increasing importance of environmental mycobacteria, detection and identification of mycobacteria from environmental sources including water have been fraught with technical difficulties. Although, several protocols to optiruize isolation of mycobacteria from water sources have been reported, standard method has not yet been established. In this study, usefulness of cetylpyridinium chloride (CPC), a cationic quaternary ammonium compound, for the isolation of environmental mycobacteria from diverse water samples was evaluated. For this, water samples from diverse water sources such as effluent water, lake water, and underground water were collected, treated with diverse concentrations of CPC, and plated on the solid agar plates. Subsequently individual colonies grown on the plates were sequence analyzed for identification of each colony. In brief, the results from this study showed that the growth of mycobacteria was enhanced by use of CPC as a pre-treatment reagent to water samples by inhibiting growth of other non-mycobacteria in water. In fact, the effect of CPC to decontaminate non-mycobacteria for isolation of mycobacteria was better than 1~4% of NaOH, which is a routinely used decontaminating reagent widely employed for culturing mycobactera from sputum specimens. Therefore, the results from this study seems to support that the CPC pre-treatment may be useful for isolation of mycobacteria from diverse sources including clinical specimens which are often contaminated with other bacteria.