School of Environment, Tsinghua University, Beijing, 100084, China; State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China; Fujian Provincial Key Laboratory of Soil Environment Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China.
School of Environment, Tsinghua University, Beijing, 100084, China; Research Institute for Environmental Innovation (Suzhou) Tsinghua, Suzhou, 215163, China.
Environ Res. 2024 Dec 1;262(Pt 2):119964. doi: 10.1016/j.envres.2024.119964. Epub 2024 Sep 12.
Biofilms in drinking water distribution systems (DWDSs) are a determinant to drinking water biosafety. Yet, how and why pipe material and natural organic matter (NOM) affect biofilm microbial community, pathogen composition and antibiotic resistome remain unclear. We characterized the biofilms' activity, microbial community, antibiotic resistance genes (ARGs), mobile genetic elements (MGEs) and pathogenic ARG hosts in Centers for Disease Control and Prevention (CDC) reactors with different NOM dosages and pipe materials based on metagenomics assembly. Biofilms in cast iron (CI) pipes exhibited higher activity than those in polyethylene (PE) pipes. NOM addition significantly decreased biofilm activity in CI pipes but increased it in PE pipes. Pipe material exerted more profound effects on microbial community structure than NOM. Azospira was significantly enriched in CI pipes and Sphingopyxis was selected in PE pipes, while pathogen (Ralstonia pickettii) increased considerably in NOM-added reactors. Microbial community network in CI pipes showed more edges (CI 13520, PE 7841) and positive correlation proportions (CI 72.35%, PE 61.69%) than those in PE pipes. Stochastic processes drove assembly of both microbial community and antibiotic resistome in DWDS biofilms based on neutral community model. Bacitracin, fosmidomycin and multidrug ARGs were predominant in both PE and CI pipes. Both pipe materials and NOM regulated the biofilm antibiotic resistome. Plasmid was the major MGE co-existing with ARGs, facilitating ARG horizontal transfer. Pathogens (Achromobacter xylosoxidans and Ralstonia pickettii) carried multiple ARGs (qacEdelta1, OXA-22 and aadA) and MGEs (integrase, plasmid and transposase), which deserved more attention. Microbial community contributed more to ARG change than MGEs. Structure equation model (SEM) demonstrated that turbidity and ammonia affected ARGs by directly mediating Shannon diversity and MGEs. These findings might provide a technical guidance for controlling pathogens and ARGs from the point of pipe material and NOM in drinking water.
饮用水分配系统 (DWDS) 中的生物膜是饮用水生物安全性的决定因素。然而，管道材料和天然有机物 (NOM) 如何以及为何影响生物膜微生物群落、病原体组成和抗生素抗性组尚不清楚。我们基于宏基因组组装，对不同 NOM 剂量和管道材料的疾病预防控制中心 (CDC) 反应器中的生物膜活性、微生物群落、抗生素抗性基因 (ARGs)、移动遗传元件 (MGEs) 和致病性 ARG 宿主进行了表征。与聚乙烯 (PE) 管相比，铸铁 (CI) 管中的生物膜活性更高。NOM 的添加显著降低了 CI 管中的生物膜活性，但增加了 PE 管中的生物膜活性。与 NOM 相比，管道材料对微生物群落结构的影响更为深远。在 CI 管中，Azospira 显著富集，而在 PE 管中，Sphingopyxis 被选择，而在添加 NOM 的反应器中，病原体 (Ralstonia pickettii) 大量增加。CI 管中的微生物群落网络显示出更多的边缘 (CI 13520，PE 7841) 和正相关比例 (CI 72.35%，PE 61.69%)，而 PE 管中的微生物群落网络则较少。基于中性群落模型，随机过程驱动 DWDS 生物膜中微生物群落和抗生素抗性组的组装。在 PE 和 CI 管中，杆菌肽、福米霉素和多药 ARGs 均占主导地位。两种管道材料和 NOM 均调节生物膜抗生素抗性组。质粒是与 ARGs 共存的主要 MGE，促进了 ARG 的水平转移。病原体 (Achromobacter xylosoxidans 和 Ralstonia pickettii) 携带多种 ARGs (qacEdelta1、OXA-22 和 aadA) 和 MGEs (整合酶、质粒和转座酶)，值得更多关注。微生物群落对 ARG 变化的贡献大于 MGEs。结构方程模型 (SEM) 表明，浊度和氨通过直接介导 Shannon 多样性和 MGEs 来影响 ARGs。这些发现可能为从饮用水中管道材料和 NOM 的角度控制病原体和 ARGs 提供技术指导。
