Abstract：
Drinking water distribution systems (DWDSs) are important for supplying high-quality water to consumers and disinfectant is widely used to control microbial regrowth in DWDSs. However, the disinfectant\'s influences on microbial community and antibiotic resistome in DWDS biofilms and the underlying mechanisms driving their dynamics remain elusive. The study investigated the effects of chlorine and chloramine disinfection on the microbiome and antibiotic resistome of biofilms in bench-scale DWDSs using metagenomics assembly. Additionally, the biofilm activity and viability were monitored based on adenosine triphosphate (ATP) and flow cytometer (FCM) staining. The results showed that both chlorine and chloramine disinfectants decreased biofilm ATP, although chloramine at a lower dosage (1 mg/L) could increase it. Chloramine caused a greater decrease in living cells than chlorine. Furthermore, the disinfectants significantly lowered the microbial community diversity and altered microbial community structure. Certain bacterial taxa were enriched, such as Mycobacterium, Sphingomonas, Sphingopyxis, Azospira, and Dechloromonas. Pseudomonas aeruginosa exhibited high resistance towards disinfectants. The disinfectants also decreased the complexity of microbial community networks. Some functional taxa (e.g., Nitrospira, Nitrobacter, Nitrosomonas) were identified as keystones in chloramine-treated DWDS microbial ecological networks. Stochasticity drove biofilm microbial community assembly, and disinfectants increased the contributions of stochastic processes. Chlorine had greater promotion effects on antibiotic resistance genes (ARGs), mobile genetic elements (MGEs) and ARG hosts than chloramine. The disinfectants also selected pathogens, such as Acinetobacter baumannii and Klebsiella pneumonia, and these pathogens also harbored ARGs and MGEs. Overall, this study provides new insights into the effects of disinfectants on biofilm microbiome and antibiotic resistome, highlighting the importance of monitoring and managing disinfection practices in DWDSs.
摘要：
饮用水分配系统（DWDS）对于向消费者提供高质量的水很重要，并且消毒剂被广泛用于控制DWDS中的微生物再生。然而,消毒剂对DWDS生物膜中微生物群落和抗生素耐药性的影响以及驱动其动力学的潜在机制仍然难以捉摸。该研究使用宏基因组学组装研究了氯和氯胺消毒对实验室规模DWDS中生物膜微生物组和抗生素抗性组的影响。此外,基于三磷酸腺苷(ATP)和流式细胞仪(FCM)染色监测生物膜活性和活力。结果表明，氯和氯胺消毒剂都能降低生物膜ATP，尽管较低剂量（1mg/L）的氯胺可以增加它。氯胺比氯引起活细胞更大的减少。此外，消毒剂显著降低了微生物群落多样性，改变了微生物群落结构。某些细菌分类群被富集，如分枝杆菌，鞘氨醇单胞菌,Sphingopyxis,偶氮螺,和脱氯单胞菌.铜绿假单胞菌对消毒剂表现出很高的抗性。消毒剂还降低了微生物群落网络的复杂性。一些功能分类单元(例如，硝基螺旋体,硝化细菌,亚硝化单胞菌）被鉴定为氯胺处理的DWDS微生物生态网络中的基石。随机性驱动生物膜微生物群落组装，消毒剂增加了随机过程的贡献。氯对抗生素抗性基因(ARGs)有较大的促进作用,移动遗传元件(MGEs)和ARG宿主比氯胺。消毒剂还选择了病原体，如鲍曼不动杆菌和肺炎克雷伯菌，这些病原体还含有ARG和MGE。总的来说,这项研究为消毒剂对生物膜微生物组和抗生素抗性组的影响提供了新的见解，强调监测和管理DWDS消毒实践的重要性。
