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Establishment and Early Succession of Bacterial Communities in Monochloramine-Treated Drinking Water Biofilms
Citation:
Revetta, R. P., V. Gomez-Alvarez, T. L. Gerke, C. Curioso, J. W. Santodomingo, AND Nicholas J. Ashbolt. Establishment and Early Succession of Bacterial Communities in Monochloramine-Treated Drinking Water Biofilms. FEMS Microbiology Ecology. Federation of European Microbiological Societies, Blackwell Publishing, , Uk, 86(3):404-414, (2013).
Impact/Purpose:
To share information with the science community.
Description:
Monochloramine is increasingly used as a drinking water disinfectant because it forms lower levels of regulated disinfection by-products. While its use has been shown to increase nitrifying bacteria, little is known about the bacterial succession within biofilms in monochloramine-treated systems. The microbial composition of biofilm and drinking water was examined by analyzing 16S rRNA gene clone libraries generated from a pipe-loop over a period of eight months. No significant differences in community structure were observed between biofilm capturing devices or coupon material used. However, differences in community structure were evident when samples were grouped by month, suggesting that all biofilm communities that developed on different devices underwent similar successions over time. Early stages of biofilm formation were dominated by Serratia (29%), Cloacibacterium (23%), Diaphorobacter (16%), and Pseudomonas (7%), while Mycobacterium-like phylotypes were the most predominant populations (>27%) in subsequent months. The Mycobacterium-like sequences identified were closely related to members of the nontuberculous mycobacteria, often isolated from potable water supplies, of which some have been implicated in outbreaks targeting individuals with predisposing conditions. In addition, planktonic communities appeared to share different distribution of members compared to biofilms. Overall, 90% of the diversity in all the clone library samples was associated with the phyla Proteobacteria, Actinobacteria and Bacteroidetes. These results are consistent with the view that monochloramine-treated drinking water provides favorable conditions for mycobacteria and other potential opportunistic pathogens (e.g. P. aeruginosa), which may be encouraged by the development of nitrifiers and other community members.
