Shaw Jennifer L A, Monis Paul, Weyrich Laura S, Sawade Emma, Drikas Mary, Cooper Alan J
Australian Centre for Ancient DNA, University of Adelaide, Adelaide, South Australia, Australia.
Australian Water Quality Centre, South Australia Water Corporation, Adelaide, South Australia, Australia
Appl Environ Microbiol. 2015 Sep;81(18):6463-73. doi: 10.1128/AEM.01297-15. Epub 2015 Jul 10.
Drinking water assessments use a variety of microbial, physical, and chemical indicators to evaluate water treatment efficiency and product water quality. However, these indicators do not allow the complex biological communities, which can adversely impact the performance of drinking water distribution systems (DWDSs), to be characterized. Entire bacterial communities can be studied quickly and inexpensively using targeted metagenomic amplicon sequencing. Here, amplicon sequencing of the 16S rRNA gene region was performed alongside traditional water quality measures to assess the health, quality, and efficiency of two distinct, full-scale DWDSs: (i) a linear DWDS supplied with unfiltered water subjected to basic disinfection before distribution and (ii) a complex, branching DWDS treated by a four-stage water treatment plant (WTP) prior to disinfection and distribution. In both DWDSs bacterial communities differed significantly after disinfection, demonstrating the effectiveness of both treatment regimes. However, bacterial repopulation occurred further along in the DWDSs, and some end-user samples were more similar to the source water than to the postdisinfection water. Three sample locations appeared to be nitrified, displaying elevated nitrate levels and decreased ammonia levels, and nitrifying bacterial species, such as Nitrospira, were detected. Burkholderiales were abundant in samples containing large amounts of monochloramine, indicating resistance to disinfection. Genera known to contain pathogenic and fecal-associated species were also identified in several locations. From this study, we conclude that metagenomic amplicon sequencing is an informative method to support current compliance-based methods and can be used to reveal bacterial community interactions with the chemical and physical properties of DWDSs.
饮用水评估使用多种微生物、物理和化学指标来评估水处理效率和产水质量。然而,这些指标无法对可能对饮用水分配系统(DWDSs)性能产生不利影响的复杂生物群落进行表征。使用靶向宏基因组扩增子测序可以快速且低成本地研究整个细菌群落。在此,对16S rRNA基因区域进行扩增子测序,并结合传统水质测量方法,以评估两个不同的全尺寸DWDSs的健康状况、水质和效率:(i)一个线性DWDS,供应未经过滤的水,在分配前进行基本消毒;(ii)一个复杂的分支DWDS,在消毒和分配前由四级水处理厂(WTP)处理。在两个DWDSs中,消毒后细菌群落均有显著差异,表明两种处理方式均有效。然而,细菌在DWDSs中进一步重新繁殖,一些终端用户样本与原水的相似性高于消毒后的水。三个采样点似乎发生了硝化作用,硝酸盐水平升高,氨水平降低,并且检测到了硝化细菌物种,如硝化螺菌属。伯克霍尔德氏菌目在含有大量一氯胺的样本中含量丰富,表明对消毒具有抗性。在几个地点还鉴定出了已知含有致病和粪便相关物种的属。从这项研究中,我们得出结论,宏基因组扩增子测序是一种有用的方法,可支持当前基于合规性的方法,并可用于揭示细菌群落与DWDSs化学和物理性质之间的相互作用。