Li Haibei, Yu Hongling, Liang Yongbing, Zhang Xudong, Yang Dong, Wang Lin, Shi Danyang, Chen Tianjiao, Zhou Shuqing, Yin Jing, Yang Zhongwei, Li Junwen, Jin Min
Department of Environment and Health, Tianjin Institute of Environmental & Operational Medicine, Key Laboratory of Risk Assessment and Control for Environment & Food Safety, Tianjin, 300050, China.
Water Quality Monitoring Center of Tianjin Water Group Co. Ltd, Tianjin, 300240, China.
Water Res. 2023 Apr 1;232:119689. doi: 10.1016/j.watres.2023.119689. Epub 2023 Feb 1.
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 (NH-N) concentration, presenting a linear upward trend with an increase in the NH-N concentration. This indicated that NH-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.
氯胺消毒和氯化消毒都是强有力的屏障，可防止潜在病原体通过饮用水传播给人类。然而，氯胺消毒和氯化消毒对饮用水处理厂（DWTPs）中抗生素抗性基因（ARGs）出现的比较影响仍不清楚。在此，通过宏基因组测序分析了氯胺消毒或氯化消毒前后水中的抗生素抗性组，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，氯胺消毒导致水中细胞内ARGs（iARGs）的总相对丰度比氯化消毒有更高的富集，而氯化消毒比氯胺消毒促进释放更多的细胞外ARGs（eARGs）。根据冗余分析和皮尔逊分析，成品水中观察到的iARGs总浓度与铵氮（NH-N）浓度呈强正相关，随着NH-N浓度的增加呈线性上升趋势。这表明NH-N是氯胺消毒过程中iARG积累的关键驱动因素。如果将氯胺消毒时间缩短至40分钟，iARG富集就会停止，这表明缩短时间将是控制饮用水中iARG富集的更好策略。这些发现强调了延长氯胺消毒后抗生素抗性的潜在风险，为通过优化DWTPs中的消毒程序来控制抗生素抗性细菌通过水传播提供了思路。
