Full Description

The description of microorganisms inhabiting drinking water distribution systems has commonlybeen performed using techniques that are biased towards easy to culture bacterial populations. Asmost environmental microorganisms cannot be grown on artificial media, the understanding ofthe microbial community structure of drinking water is very limited. To circumvent some of theproblems associated with culture-based techniques, sequence analysis of 16S rRNA gene clonelibraries was used in this study. Genomic DNA was extracted from bulk phase water fromsampling sites within the distribution systems (WDS), and used to develop 16S rRNA geneclone libraries. Water samples were collected from areas within the distribution system fed bytwo distinct raw water sources. Over 2300 16S rDNA clones were analyzed in this study from atotal of 31 different sites. Phylogenetic analyses showed that a-Proteobacteria and Actinobacteriarepresented more than 90% of the total clones examined. In general, similar bacterial groupswere observed in sites receiving groundwater and surface water sources suggesting thatchlorination is an important selective force in shaping up the overall microbial communitystructure. While the communities were similar at the general bacterial group, there were somedifferences at finer phylogenetic levels. This is important as it suggests that differences in thesources and treatment technologies could select for different populations. Since more than half ofthe clones were associated with yet to be cultured bacteria, and in many cases with novelbacterial groups, the results further substantiate the need for the development of culture-independent methods to better identify drinking water and to study their in situ spatial temporal dynamics. Includes 36 references, figures.

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Edition: Vol. - No. Published: 11/01/2009 Number of Pages: 12File Size: 1 file , 1.1 MB