摘要
      氯胺化和氯化都是防止潜在病原体通过饮用水传播给人类的强大屏障。然而，氯胺化和氯化对饮用水处理厂（DWTP）抗生素耐药性基因（ARGs）发生的比较影响仍然未知。本文通过宏基因组测序分析氯胺或氯化前后水中的抗生素耐药性，然后通过定量实时聚合酶链反应（qPCR）进行验证。处理90分钟后，氯胺导致水中细胞内ARGs（iARGs）的总相对丰度比氯化更高，而氯化比氯胺促进更多细胞外ARGs的释放。根据冗余度和Pearson分析，成品水中观察到的iARGs总浓度与铵态氮（NH4+–N）浓度呈强正相关，随着NH4+-N浓度的增加呈线性上升趋势。这表明NH4+–N是氯胺化过程中iARG积累的关键驱动因素。如果氯胺化的持续时间缩短到40分钟，iARG的富集就会停止，这表明缩短持续时间将是控制饮用水中iARG富集的更好策略。这些发现强调了长期氯胺化后抗生素耐药性的潜在风险，为通过优化DWTP的消毒程序来控制抗生素耐药性细菌通过水的传播提供了线索。
Abstract
Chloramination and chlorination are both strong barriers that prevent the transmission of potential pathogens to humans through drinking water. However, the comparative effects of chloramination and chlorination on the occurrence of antibiotic resistance genes (ARGs) in drinking water treatment plants (DWTPs) remain unknown. Herein, the antibiotic resistome in water before and after chloramination or chlorination was analyzed through metagenomic sequencing and then verified through quantitative real-time polymerase chain reaction (qPCR). After the treatment of 90 min, chloramination led to higher enrichment of the total relative abundance of intracellular ARGs (iARGs) in water than chlorination, whereas chlorination facilitated the release of more extracellular ARGs (eARGs) than chloramination. According to redundancy and Pearson's analyses, the total concentration of the observed iARGs in the finished water exhibited a strong positive correlation with ammonium nitrogen (NH4+–N) concentration, presenting a linear upward trend with an increase in the NH4+–N concentration. This indicated that NH4+–N is a crucial driving factor for iARG accumulation during chloramination. iARG enrichment ceases if the duration of chloramination is shortened to 40 min, suggesting that shortening the duration would be a better strategy for controlling iARG enrichment in drinking water. These findings emphasized the potential risk of antibiotic resistance after extended chloramination, shedding light on the control of transmission of antibiotic-resistant bacteria through water by optimizing disinfection procedures in DWTPs.

https://www.sciencedirect.com/science/article/abs/pii/S0043135423001240