[Analysis of microbial community of a Beijing simulator water distribution system]

Identification of compositions of the biofilm in a Beijing simulator water distribution system pipe networks by PCR and single strand conformation polymorphism (PCR-SSCP) technique and analysis of its heterotrophic bacterial by heterotrophic plate count (HPC) were performed. Results showed that when the water velocities were same, the count of heterotrophic bacterial on the zinficated steel wall was about five times of the PVC. On the other hand, when the pipe materials were zinficated steel, the count of heterotrophic bacterial in the deadwater pipe wall was about 1/5 of the 0.6 m/s region. The difference of the bacterial count maybe related to the smooth of the water pipe surface and the velocity of flow which affected the attachment of the microorganisms and the quantity of O2 and nourishment, respectively. Same SSCP electrophoresis profiles were observed between samples from different material pipes and water velocities. After sequencing and contrasting with the GenBank, the identity of three bands from the SSCP gel with Bacillus cereus (GenBank AB190077), Peudomonas sp. yged143 (GenBank EF419342) and a unclassified bacteria, Bacterium UASWS0134 (GenBank DQ190347) were 100%, 99% and 94%, respectively. The sameness of the microbial community structure may be induced by the samples which were from the same simulator system and the sampling regions were near and the microorganisms could transform in these regions easily. The observed potential pathogens of Bacillus cereus and Peudomonas sp. should lead to a consideration of the microbiology safety of drinking water.