摘要
      抗生素耐药性基因（ARGs）是一个新出现的饮用水安全问题。然而，饮用水分配系统中ARGs的季节变化仍不清楚。这项工作通过宏基因组组装揭示了DWDS散装水中微生物群落、ARGs、与ARGs共存的移动遗传元件（MGE）、ARG宿主的时空变化。微生物群落和抗生素耐药性随采样季节和采样地点的不同而变化。温度、氨、亚氯酸盐和总平板数（TPC）驱动了微生物群落结构的变化。此外，环境参数（总有机碳（TOC）、亚氯酸盐、TPC和硬度）改变了抗生素耐药性。与ARGs共存的ARGs和MGEs在夏季和秋季表现出较高的相对丰度，这可能归因于管道生物膜的分离。特别是，ARG杆菌肽和质粒分别是主要的ARG和MGE。ARG宿主随着季节和地点的变化而变化，在夏季和秋季更加多样化。在冬季和春季，Limnohabitans和分枝杆菌是ARG的主要宿主，也是微生物群落中的优势属。此外，在夏季和秋季，相对丰度较高的无色杆菌和狭窄单胞菌是在居民区（距离水处理厂0.4公里）内携带多种ARG和MGE的宿主。与MGEs相比，微生物群落对抗生素耐药性的变化有更大的贡献。这项工作为全尺寸DWDS中ARG的动力学和潜在因素提供了新的见解。
Abstract
Antibiotic resistance genes (ARGs) are an emerging issue for drinking water safety. However, the seasonal variation of ARGs in drinking water distribution systems (DWDS) is still unclear. This work revealed the tempo-spatial changes of microbial community, ARGs, mobile genetic elements (MGEs) co-occurring with ARGs, ARG hosts in DWDS bulk water by means of metagenome assembly. The microbial community and antibiotic resistome varied with sampling season and site. Temperature, ammonia, chlorite and total plate count (TPC) drove the variations of microbial community structure. Moreover, environmental parameters (total organic carbon (TOC), chlorite, TPC and hardness) shifted antibiotic resistome. ARGs and MGEs co-occurring with ARGs showed higher relative abundance in summer and autumn, which might be attributed to detached pipe biofilm. In particular, ARG-bacitracin and plasmid were the predominant ARG and MGE, respectively. ARG hosts changed with season and site and were more diverse in summer and autumn. In winter and spring, Limnohabitans and Mycobacterium were the major ARG hosts as well as the dominant genera in microbial community. In addition, in summer and autumn, high relative abundance of Achromobacter and Stenotrophomonas were the hosts harboring many kinds of ARGs and MGEs at site in a residential zone (0.4 km from the water treatment plant). Compared with MGEs, microbial community had a greater contribution to the variation of antibiotic resistome. This work gives new insights into the dynamics of ARGs in full-scale DWDS and the underlying factors.

https://www.sciencedirect.com/science/article/abs/pii/S1001074222003540