摘要

      水回收利用为满足不可利用的用水需求提供了宝贵的资源。然而，人们对废水回用传播抗生素耐药基因（ARGs）的潜力知之甚少。在这里，2014-2015年季节性地从四个美国公用事业公司的再生水和饮用水分配系统收集了处理前、处理后和五个使用点（POU）的样品。用鸟枪亚基因组测序法对样本子集（n=38）的抵抗性组（即，全部ARGs）进行了分析。用定量聚合酶链反应（qnrA、blaTEM、vanA、sul1）对4种ARGs进行定量分析。研究了细菌群落组成（通过16srRNA基因扩增子测序）、水平基因转移（通过定量intI1整合酶和质粒基因）和选择压力（通过检测金属和抗生素）作为控制ARGs存在的潜在因素。与相应的饮用样品相比，所有（sul1；p≤0.0011）或某些（blaTEM，qnrA；p≤0.0145）回收的POU样品中的某些ARG升高。细菌群落组成与ARGs（Adonis，R2=0.1424-0.1734）呈弱相关，193个ARGs与质粒相关基因存在相关性。这项研究证实，再生水比饮用水能输送更多的ARGs，并就可能控制再生水系统中ARGs发生的因素提供了观察。

      Water reclamation provides a valuable resource for meeting nonpotable water demands. However, little is known about the potential for wastewater reuse to disseminate antibiotic resistance genes (ARGs). Here, samples were collected seasonally in 2014-2015 from four U.S. utilities' reclaimed and potable water distribution systems before treatment, after treatment, and at five points of use (POU). Shotgun metagenomic sequencing was used to profile the resistome (i.e., full contingent of ARGs) of a subset ( n = 38) of samples. Four ARGs ( qnrA, bla_TEM, vanA, sul1) were quantified by quantitative polymerase chain reaction. Bacterial community composition (via 16S rRNA gene amplicon sequencing), horizontal gene transfer (via quantification of intI1 integrase and plasmid genes), and selection pressure (via detection of metals and antibiotics) were investigated as potential factors governing the presence of ARGs. Certain ARGs were elevated in all ( sul1; p ≤ 0.0011) or some ( bla_TEM, qnrA; p ≤ 0.0145) reclaimed POU samples compared to corresponding potable samples. Bacterial community composition was weakly correlated with ARGs (Adonis, R² = 0.1424-0.1734) and associations were noted between 193 ARGs and plasmid-associated genes. This study establishes that reclaimed water could convey greater abundances of certain ARGs than potable waters and provides observations regarding factors that likely control ARG occurrence in reclaimed water systems.

       https://pubs.acs.org/doi/10.1021/acs.est.7b05419