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Abstract：
Appropriate management approaches are needed to minimize the proliferation of antibiotic resistance genes (ARGs) in reclaimed water distribution systems (RWDSs). Six laboratory-scale RWDSs were operated over 3 years receiving influent with or without biologically active carbon (BAC) filtration + chlorination, chloramination, or no disinfectant residual. Shotgun metagenomic sequencing was applied toward comprehensive characterization of resistomes, focusing on total ARGs, ARG mobility, and specific ARGs of clinical concern. ARGs such as aadA, bacA, blaOXA, mphE, msrE, sul1, and sul2 were found to be particularly sensitive to varying RWDS conditions. BAC filtration with chlorination most effectively achieved and maintained the lowest levels of nearly all metagenomically derived antibiotic resistance indicators. However, BAC filtration or addition of residual disinfectants alone tended to increase these indicators. Biofilm and sediment compartments harbored ARGs in disinfected systems, presenting a concern for their release to bulk water. Relative and absolute abundances of most ARGs tended to decrease with water age (up to 5 days), with notable exceptions in BAC-filtered chloraminated and no residual systems. Superchlorination of unfiltered water especially raised concerns in terms of elevation of clinically relevant and mobile ARGs. This study revealed that BAC filtration and disinfection must be carefully coordinated in order to effectively mitigate ARG dissemination via RWDSs.
摘要：
需要适当的管理方法来最大程度地减少再生水分配系统（RWDS）中抗生素抗性基因（ARG）的增殖。六个实验室规模的RWDS在3年内运行，接收有或没有生物活性炭（BAC）过滤+氯化的进水，氯胺化,或无消毒剂残留。鸟枪宏基因组测序被应用于全面表征抗性，专注于总ARG，ARG移动性,和临床关注的特定ARGs。ARGs如AADA,baca,blaOXA,mphe,msrE,sul1和sul2被发现对变化的RWDS条件特别敏感。具有氯化的BAC过滤最有效地实现并保持了几乎所有宏基因来源的抗生素抗性指标的最低水平。然而,BAC过滤或单独添加残留消毒剂倾向于增加这些指标。生物膜和沉积物隔室在消毒系统中含有ARG，对它们释放到散装水中表示担忧。大多数ARGs的相对和绝对丰度随着水龄(最多5天)而下降。在BAC过滤的氯胺化和无残留系统中，有明显的例外。未过滤水的超氯化特别引起了临床相关和可移动ARG升高的担忧。这项研究表明，必须仔细协调BAC过滤和消毒，以有效减轻通过RWDS传播的ARG。
