摘要

了解抗生素抗性基因（ARGs）在饮用水处理过程中如何分布是非常重要的，因为它们有潜在的公共健康风险。对黄河特别是流域规模的典型饮用水处理工艺如沉砂池（SSRs）和饮用水处理厂（DWTPs）的ARGs的发生和分布知之甚少。本研究利用实时定量聚合酶链式反应（qPCR）对黄河沿岸六个城市SSRs和DWTPs进水（河水）和污水（源水）水样进行ARG分析， 16S rRNA基因测序。检测到17个ARGs和2个移动遗传元件（MGEs），其中aadE，strA，strB，tetA，sulII，intl1和Tn916的检出率很高（超过80％）。 ARGs的绝对丰度（基因拷贝/ mL水）通常由SSRs和DWTPs降低，但ARGs的相对丰度（基因拷贝/ 16S rRNA基因）没有观察到减少。没有观察到ARG和细菌的空间分布。细菌属的分布在不同水型样品中聚集成四种主要模式。细菌属假单胞菌属，Massilia属，不动杆菌属，鞘氨醇单胞菌属，甲基杆菌属和Brevundimonas占主导地位，Brevundimonas和Methylobacterium通过网络分析被推测为两个ARGs（strA和strB）的潜在宿主。可能由选择消毒过程引起的这两个属的富集可能有助于成品水中ARG的较高相对丰度。本研究为流域规模的饮用水处理过程中的ARG潜在风险提供了深入的见解和有效的评估。

Understanding how antibiotic resistance genes (ARGs) are distributed in drinking water treatment processes is important due to their potential public health risk. Little is known about the occurrence and distribution of ARGs in typical drinking water treatment processes, such as sand settling reservoirs (SSRs) and drinking water treatment plants (DWTPs), in the Yellow River, especially at the catchment scale. In this study, ARG profiling was investigated from water samples of influent (river water) and effluent (source water) of SSRs and finished water of DWTPs in six cities along the Yellow River catchment using real-time quantitative polymerase chain reaction (qPCR) and 16S rRNA gene sequencing. Seventeen ARGs and two mobile genetic elements (MGEs) were detected, among which aadE, strA, strB, tetA, sulII, intl1, andTn916 had high detection rates (over 80%). The absolute abundances (gene copies/mL of water) of ARGs were reduced by the SSRs and DWTPs generally, but no reductions were observed for the relative abundances (gene copies/16S rRNA gene) of ARGs. Spatial distributions of ARGs and bacteria were not observed. The distribution of bacterial genera was clustered into four dominant patterns in different water type samples. The bacterial genera Pseudomonas, Massilia, Acinetobacter, Sphingomonas,Methylobacterium, and Brevundimonas dominated the finished water, with Brevundimonas andMethylobacterium being speculated to be potential hosts for two ARGs (strA and strB) through network analysis. The enrichment of these two genera, likely caused by selection of disinfection process, may contribute to the higher relative abundance of ARGs in finished water. This study provides insight and effective assessment of the potential risk of ARGs in drinking water treatment processes at the catchment scale. 

http://www.mdpi.com/2073-4441/10/3/246