摘要

      评价了侧向流砂滤池作为现场污水处理系统（OWTS）去除抗药性基因（ARGs）、抗药性细菌（ARB）和其他相关遗传标记（HF183、16srrna和int1）的能力。城市污水在装入由三种不同砂介质组成的六个中试规模侧流砂滤池之前，在5%和30%的坡度下，在化粪池中沉淀。从2017年7月至11月，每两周对砂滤器进行一次采样，以获得9个ARGs和3个其他免费基因标记（sul1、sul2、qnrS、tetO、ermB、blaTEM、blaCTX-M、mecA、vanA、int1、HF183、16srrna）以及常规微生物和水质指标，并在2018年夏季进行4次采样。在6个砂滤器中，有5个砂滤器去除了化粪池废水中的ARGs绝对丰度，观察到从2.9到5.4 log的对数减少。由于水力破坏，5%斜坡上的细粒度过滤器对ARG的衰减效果不好。基因标记的细胞相关DNA与无细胞DNA的比例测定表明，基因主要在细胞内携带。与化粪池污水相比，滤池内对磺胺甲恶唑、红霉素或四环素耐药的ARB的平均对数减少量约为2.3 log CFU/mL。这项实地研究为ARB、ARGs在不同饱和砂土中的衰减及其遗传分区提供了深入的见解。总的来说，当维持适当的液压功能时，这种类型的OWT被发现对传播到周围环境的抗微生物污染的风险很小。

      The ability of lateral flow sand filters, used as on-site wastewater treatment systems (OWTS), to remove antibiotic resistance genes (ARGs), antibiotic resistant bacteria (ARB), and other relevant genetic markers (HF183, 16S rRNA, and int1) was assessed. Municipal wastewater was settled in a septic tank prior to loading into six pilot-scale lateral flow sand filters comprised of three different sand media types, at 5 and 30% slopes. The sand filters were sampled bi-weekly for: 9 ARGs and 3 other complimentary gene markers (sul1, sul2, qnrS, tetO, ermB, bla_TEM, bla_CTX-M, mecA, vanA, int1, HF183, 16S rRNA), and conventional microbial and water quality indicators, from July to November in 2017, and four times in the summer of 2018. The sand filters were observed to attenuate 7 of the ARGs to mostly below 2 log gene copies per mL. Log reductions ranging from 2.9 to 5.4 log were observed for the removal of absolute abundances of ARGs from septic tank effluent in 5 of the 6 sand filters. The fine-grained filter on the 5% slope did not perform as well for ARG attenuation due to hydraulic failure. The apportionment of cell-associated versus cell-free DNA was determined for the gene markers and this indicated that the genes were primarily carried intracellularly. Average log reductions of ARB with resistance to either sulfamethoxazole, erythromycin, or tetracycline were approximately 2.3 log CFU per mL within the filters compared to the septic tank effluent. This field study provides in-depth insights into the attenuation of ARB, ARGs, and their genetic compartmentalization in variably saturated sand OWTS. Overall, this type of OWTS was found to pose little risk of antimicrobial resistance contamination spread into surrounding environments when proper hydraulic function was maintained.

       https://www.sciencedirect.com/science/article/abs/pii/S0043135419306037?via%3Dihub