摘要
      抗生素耐药性基因（ARGs）被认为是新出现的环境污染物。饮用水中的耐药性（所有ARGs的集合）及其在饮用水处理过程中的命运尚不清楚。本研究应用宏基因组组装和网络分析相结合的方法，在两个全面的饮用水处理厂（DWTP）中破译了抗性体的分布、迁移率、宿主和致病性，每个工厂都应用了臭氧氧化的常规处理和高级处理，然后是生物活性炭过滤。在从两个DWTP收集的每个处理过程的源水和废水中，检测到属于20种类型的215种ARG，总浓度范围为6.30±1.83至5.20±0.26×104拷贝/mL。传统和先进的DWTP都能有效降低总ARGs的浓度，平均去除效率分别为3.61-log10和2.21-log10。多项统计分析（包括网络分析）表明，饮用水耐药性与移动基因元件（MGE）和细菌群落密切相关，后者是DWTP耐药性改变的主要驱动因素。对从饮用水宏基因组组装的携带ARG的重叠群（ACC）的进一步分析（i）追踪ARG的潜在细菌宿主（例如，作为主要耐药菌群的变形杆菌门），（ii）提供了ARG和MGE的共定位信息（例如，MacB-E7196质粒1），以及（iii）鉴定了携带ARG人类病原体（例如，粪肠球菌和尖刺雷氏菌）。这项工作首先确定了DWTP耐药性的浓度、迁移率和致病率，在此基础上可以在进一步的研究中定量评估抗生素耐药性的实际健康风险，为DWTP中ARGs的风险控制决策提供了有用的指导。
Abstract
Antibiotic resistance genes (ARGs) have been regarded as emerging environmental contaminants. The profile of resistome (collection of all ARGs) in drinking water and its fate during drinking water treatment remain unclear. This study applied metagenomic assembly combined with network analysis to decipher the profile, mobility, host, and pathogenicity of resistomes in two full-scale drinking water treatment plants (DWTPs), each applying conventional treatment and advanced treatment of ozonation followed by biological activated carbon filtration. In source waters and effluents of each treatment process collected from both DWTPs, 215 ARGs belonging to 20 types were detected with total concentration ranging from 6.30 ± 1.83 to 5.20 ± 0.26 × 104 copies/mL. Both the conventional and advanced DWTPs were revealed to effectively reduce the concentration of total ARGs, with the average removal efficiency of 3.61-log10 and 2.21-log10, respectively. Multiple statistical analyses (including network analysis) indicated drinking water resistome correlated tightly with mobile gene elements (MGEs) and bacterial community, with the latter acting as the premier driver of resistome alteration in DWTPs. Further analysis of ARG-carrying contigs (ACCs) assembled from drinking water metagenomes (i) tracked down potential bacterial hosts of ARGs (e.g., Proteobacteria phylum as the major pool of resistome), (ii) provided co-localization information of ARGs and MGEs (e.g., MacB-E7196 plasmid1), and (iii) identified ARG-carrying human pathogens (e.g., Enterococcus faecium and Ralstonia pickettii). This work firstly determined the concentration, mobility incidence, and pathogenicity incidence of DWTP resistomes, based on which the actual health risk regarding antibiotic resistance could be quantitatively assessed in further study, providing a useful direction for decision-making concerning the risk control of ARGs in DWTPs.

https://www.sciencedirect.com/science/article/abs/pii/S0048969721051706