To give an insight into the bacterial diversity of biofilms from full-scale drinking water distribution systems (DWDSs), the bacterial community compositions of biofilms from two urban DWDSs were determined using a 16S rRNA gene library technique. Meanwhile, the occurrence and diversity of mycobacteria were also analyzed by a Mycobacterium-specific hsp gene assay. The biofilms from the full-scale DWDSs have complex bacterial populations. Proteobacteria was the common and predominant group in all biofilm samples, in agreement with previous reports. The community structures of bacteria at the three sites in the south urban DWDS were significantly different, despite the similar physicochemical properties of portable water. Some abundant and peculiar bacterial phylotypes were noteworthy, including Methylophilus, Massilia, and Planomicrobium, members of which are rarely found in DWDSs and their roles in DWDS biofilms are still unclear. The diversity of Mycobacterium species in biofilm samples was rather low. Mycobacterium arupense and Mycobacterium gordonae were the primary Mycobacterium species in the south and north urban DWDS biofilms, respectively, indicating that M. arupense may be more resistant to chloride than M. gordonae.
Those findings were observed by Dr. LIU Ruyin, assistant professor of CRE, who has spent almost two years on this research. He, as well as his group, will continue their research and are expected to identify some key factors associated with drinking water security.
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Phylogenetic analysis of hsp gene sequences of Mycobacterium spp.
