摘要

      饮用水源中抗生素耐药基因（ARGs）的污染可能对人体健康构成直接威胁。本研究应用基因组测序和分析方法，对淮河流域中上游12个饮用水源地的ARG模式进行了研究。根据冗余分析和多元线性回归模型，饮用水源地的地理位置、特定微生物类群、牲畜数量和卫生设施对ARG剖面有显著影响。除平原和基岩山区样品中ARG的聚集效应外，裂隙含水层样品也表现出与孔隙含水层样品不同的生物地理格局。推测ARGs寄主opittus和黄杆菌分别是平原和裂隙含水层富集的生物标志物，主要携带杆菌肽、多药、β-内酰胺和四环素ARGs。这一结果说明，流域内自然背景和人为活动对天然淡水系统中的ARG剖面都有显著影响。MGEs丰度低，病原菌不存在，表明采样饮用水源中ARG的传播风险较低，而多核菌是ARGs的丰富宿主，与ARG分布有显著的相关性，表明特定的细菌是ARGs在地表淡水系统中传播和积累的主要原因。需要进一步的研究来评估人类接触饮用水源的潜在风险，以及微生物群落中的物种相互作用及其对贫营养条件下ARG繁殖的影响。

       The contamination with antibiotic resistance genes (ARGs) in raw drinking water source may pose a direct threat to human health. In this study, metagenomics sequencing and analysis were applied to investigate the ARG pattern in 12 drinking water sources in upper and middle reach of Huaihe River Basin, China. Based on the redundant analysis and multi-linear regression model, location, specific microbial taxa, number of livestock and health facilities significantly influenced the ARG profile in drinking water sources. Besides the cluster effect of ARG in samples from plain and bedrock mountain areas, the samples from fracture aquifer areas also showed a distinctive biogeographic pattern with that from porous aquifer areas. Putative ARGs host Opitutus and Flavobacterium were the enriched biomarkers in plain and fracture aquifer area respectively, which mainly carried bacitracin, multidrug, beta-lactam and tetracycline ARGs. This result illuminated that both natural background and anthropogenic activities in the watershed influenced the ARG profile in natural freshwater system significantly. The low MGEs abundance and absence of pathogen revealed a low ARG dissemination risk in sampled drinking water sources, while Polynucleobacter was an abundant ARGs host and was significantly related to the ARG profile, which indicated that specific bacteria was responsible for ARGs propagation and accumulation in surface freshwater system. Further researches are needed to assess human exposure to raw drinking water source and the potential risk, as well as the species interaction in microbial community and its impact on ARG propagation under oligotrophic condition.

       https://www.sciencedirect.com/science/article/pii/S0269749118351352?via%3Dihub