北京市模拟给水管网管壁微生物膜群落分析

Analysis of Microbial Community of a Beijing Simulator Water Distribution System

以北京市模拟给水管网管壁微生物膜为研究对象,采用HPC(异养菌平板计数)和PCR-SSCP(单链构象多态性)方法,分析模拟给水管网管壁微生物膜异养菌数目和微生物群落结构.结果表明,在相同流速条件下,镀锌钢管的管壁微生物数量约为PVC管的5倍.在相同材质的镀锌钢管内,死水区的HPC计数量约为0.6 m.s-1,是流速区的1/5.计数结果的差异可能与不同材质表面的光滑度及流速造成微生物生长所需的氧气和营养基质不同有关.而不同材质和不同流速区微生物群落的SSCP电泳图谱则显示为一样,均在相同位置出现同样条带.测序结果显示,SSCP电泳图中的3条带与蜡状芽孢杆菌(Bacillus cereus,GenBank登录号为AB190077)、假单胞菌(Peudomonas sp. yged143,GenBank登录号为EF419342)和未分类细菌(Bacterium UASWS0134,GenBank登录号为DQ190347)的同源性分别为100%、99%和94%.测序结果的一致性可能与取样点为同一模拟管网,距离比较接近,不同微生物容易在其中流动和转移有关.而潜在致病菌蜡状芽孢杆菌和假单胞菌的存在则提示应该更加重视饮用水的微生物安全性.

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 heterotrophie 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 UASWSO134 （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 Peuclomonas sp. should lead to a consideration of the microbiology safety of drinking water.