摘要

  抗生素抗性基因 (ARG) 可以在水处理过程中存活下来。然而，饮用水源中抗生素抗性组的流行模式、关键驱动因素以及与机会性病原体的关系仍不清楚。在此，基于 ARG、移动遗传元件 (MGE)、细菌群落、抗生素和机会性细菌病原体对中国大地理范围内收集的 53 个饮用水样品进行了表征。通过高通量定量聚合酶链反应 (HT-qPCR) 共检测到 265 个独特的 ARG 和 MGE，超过 50% 的样本共有 101 个基因。河流中的 ARG 丰度高于水库或地下水，并且 ARG 相似性在 >4 000 km 尺度上显示出距离-衰减关系。检测到的五种机会病原体中有四种（即大肠杆菌、分枝杆菌、产气荚膜梭菌和蜡状芽孢杆菌）是 ARG 的潜在宿主。基于多变量统计，我们的结果表明，影响饮用水源抗生素耐药组的因素是多重和相互作用的。细菌群落对 ARG 结构有很大贡献，抗生素浓度和 MGE 也影响 ARG 增殖。结构方程模型表明地理位置和样本类型（即河流、水库和地下水）通过改变细菌群落和抗生素浓度对 ARG 产生间接影响。建议全面考虑自然和人为因素，以了解大地理范围内饮用水源的抗生素耐药性变异。此外，建议大规模多样化样本，以尽量减少事故或随机性的潜在影响。我们的研究结果提供了对饮用水抗生素抗性组引起的水质风险的深入了解。

   Antibiotic resistance genes (ARGs) can survive the water treatment process. However, the prevalence patterns, key drivers, and relationships with opportunistic pathogens of the antibiotic resistome harbored in drinking water sources remain unclear. Herein, 53 drinking water samples collected across a large geographical scale in China were characterized based on ARGs, mobile genetic elements (MGEs), bacterial communities, antibiotics, and opportunistic bacterial pathogens. A total of 265 unique ARGs and MGEs were detected by high-throughput quantitative polymerase chain reaction (HT-qPCR), and 101 genes were shared among over 50% of samples. ARG abundance was higher in rivers than in reservoirs or groundwater, and ARG similarity showed a distance-decay relationship at the >4 000 km scale. Four out of the five detected opportunistic pathogens (i.e., Escherichia coli, Mycobacterium spp., Clostridium perfringens, and Bacillus cereus group) were potential hosts of ARGs. Based on multivariate statistics, our results demonstrated that the factors influencing the antibiotic resistome in drinking water sources were multiple and interactive. The bacterial community greatly contributed to ARG structure, and antibiotic concentrations and MGEs also affected ARG proliferation. The structural equation model indicated that geographical location and sample types (i.e., river, reservoir, and groundwater) had indirect effects on ARGs by changing the bacterial community and antibiotic concentration. Holistic consideration of natural and anthropogenic factors is recommended to understand antibiotic resistome variation in drinking water sources at a large geographical scale. Furthermore, large-scale diverse samples are suggested to minimize the potential influence of accident or stochasticity. Our findings provide insight into water quality risks induced by drinking water antibiotic resistomes.

   https://www.sciencedirect.com/science/article/abs/pii/S0043135420306254