Williams Margaret M, Santo Domingo Jorge W, Meckes Mark C
Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
Biofouling. 2005;21(5-6):279-88. doi: 10.1080/08927010500452695.
Most water utilities use chlorine or chloramine to produce potable water. These disinfecting agents react with water to produce residual oxidants within a water distribution system (WDS) to control bacterial growth. While monochloramine is considered more stable than chlorine, little is known about the effect it has on WDS biofilms. Community structure of 10-week old WDS biofilms exposed to disinfectants was assessed after developing model biofilms from unamended distribution water. Four biofilm types were developed on polycarbonate slides within annular reactors while receiving chlorine, chloramine, or inactivated disinfectant residual. Eubacteria were identified through 16S rDNA sequence analysis. The model WDS biofilm exposed to chloramine mainly contained Mycobacterium and Dechloromonas sequences, while a variety of alpha- and additional beta-proteobacteria dominated the 16S rDNA clone libraries in the other three biofilms. Additionally, bacterial clones distantly related to Legionella were found in one of the biofilms receiving water with inactivated chlorine residual. The biofilm reactor receiving chloraminated water required increasing amounts of disinfectant after 2 weeks to maintain chlorine residual. In contrast, free chlorine residual remained steady in the reactor that received chlorinated water. The differences in bacterial populations of potable water biofilms suggest that disinfecting agents can influence biofilm development. These results also suggest that biofilm communities in distribution systems are capable of changing in response to disinfection practices.
大多数自来水公司使用氯或氯胺来生产饮用水。这些消毒剂与水发生反应，在供水系统（WDS）中产生残留氧化剂，以控制细菌生长。虽然一氯胺被认为比氯更稳定，但人们对其对供水系统生物膜的影响知之甚少。在用未处理的配水培养模型生物膜后，评估了暴露于消毒剂的10周龄供水系统生物膜的群落结构。在环形反应器内的聚碳酸酯载玻片上培养了四种生物膜类型，同时分别加入氯、氯胺或灭活的消毒剂残留。通过16S rDNA序列分析鉴定真细菌。暴露于氯胺的模型供水系统生物膜主要包含分枝杆菌属和脱氯单胞菌属序列，而在其他三种生物膜的16S rDNA克隆文库中，各种α-变形菌和其他β-变形菌占主导地位。此外，在其中一个接收含有灭活氯残留水的生物膜中发现了与军团菌属亲缘关系较远的细菌克隆。接收加氯胺水的生物膜反应器在2周后需要增加消毒剂用量以维持氯残留。相比之下，接收加氯水的反应器中游离氯残留保持稳定。饮用水生物膜中细菌种群的差异表明消毒剂会影响生物膜的形成。这些结果还表明，供水系统中的生物膜群落能够根据消毒措施发生变化。
