摘要
      由于抗生素耐药性危机，抗生素耐药性基因（ARGs）正受到越来越多的关注。然而，人们对氯化饮用水分配系统（DWDS）中细胞外ARG（eARGs）的空间行为和来源知之甚少。在这里，连续收集自来水，以揭示沿着氯化DWDS的eARGs和细胞内ARGs（iARGs）的发生。随后，进一步分析了eARGs、eDNA释放群落和浮游细菌群落之间的相关性。eARG浓度显著下降，而vanA和blaNDM-1的比例增加。此外，eDNA释放群落的多样性随着与饮用水处理厂（DWTP）距离的增加而显著增加。此外，主要的eDNA释放细菌从DWTP的成品水中的不动杆菌、假单胞菌和甲基柔红霉素转移到DWDS中的拟杆菌、粪杆菌、葡萄球菌和副拟杆菌。就eARG来源而言，30个属与7种类型的eARG显著相关，这些eARG是由死浮游细菌和分离的生物膜裂解引起的。相反，在DWDS沿线的采样点，iARGs浓度增加，而浮游细菌群落的生物多样性降低。我们的发现为eARGs的空间行为和来源提供了重要的见解，突出了DWDS中与ARGs相关的健康风险。
Abstract
Antibiotic resistance genes (ARGs) are receiving increasing concerns due to the antibiotic resistance crisis. Nevertheless, little is known about the spatial behavior and sources of extracellular ARGs (eARGs) in the chlorinated drinking water distribution systems (DWDSs). Here, tap water was continuously collected to reveal the occurrence of both eARGs and intracellular ARGs (iARGs) along a chlorinated DWDS. Afterward, the correlation between eARGs, eDNA-releasing communities, and communities of planktonic bacteria was further analyzed. The eARG concentration decreased significantly, whereas the proportion of vanA and blaNDM-1 increased. Further, the diversity of the eDNA-releasing community increased markedly with increasing distance from the drinking water treatment plant (DWTP). Moreover, the dominant eDNA-releasing bacteria shifted from Acinetobacter, Pseudomonas, and Methylobacterium-Methylorubrum in finished water from the DWTP to Bacteroides, Faecalibacterium, Staphylococcus, and Parabacteroides in the DWDS. In terms of eARG source, thirty genera were significantly correlated with seven types of eARGs that resulted from the lysis of dead planktonic bacteria and detached biofilms. Conversely, the iARGs concentration increased, whereas the biodiversity of the planktonic bacteria community decreased in the sampling points along the DWDSs. Our findings provide critical insights into the spatial behavior and sources of eARGs, highlighting the health risks associated with ARGs in DWDSs.

https://www.sciencedirect.com/science/article/abs/pii/S0304389421029113