摘要

       城市污水处理厂 (UWTP) 是抗生素耐药性 (AR) 传播到环境中的主要热点之一，目前正在研究传统和新型消毒工艺作为尽可能减少 AR 转移风险的屏障的作用。因此，这项工作的目的是评估高级氧化工艺 (AOP)（特别是 UV/H2O2）对 AR 转移电位的影响。 UV/H2O2 消毒实验在真实废水样品上进行，以评估：i) 总大肠菌群、大肠杆菌和抗生素抗性大肠杆菌的灭活，以及 ii) 可能去除目标抗生素抗性基因 (ARG)（即 blaTEM） 、qnrS 和 tetW）。特别是，DNA 是从抗生素抗性大肠杆菌细菌细胞（细胞内 DNA）中提取的，在选择性培养基上生长，以及在不同处理时间收集的整个水悬浮液（总 DNA）。进行聚合酶链反应 (PCR) 测定以检测所选 ARG 的不存在/存在。实时定量聚合酶链反应 (qPCR) 用于以拷贝数 mL-1 对研究的 ARG 进行量化。 尽管处理 60 分钟后细菌灭活且细胞内 DNA 中的 ARG 减少，但 UV/H2O2 过程无效从水悬浮液中去除 ARGs（总 DNA）。特别是，在处理 240 分钟后，在总 DNA 中观察到 blaTEM 基因的增加高达 3.7 × 103 拷贝 mL− 1 (p > 0.05)，而 qnrS 基因在初始 (5.1 × 104 份 mL− 1) 和最终样品（4.3 × 104 份 mL− 1）。根据所取得的结果，所调查的消毒过程可能无法有效地将 AR 传播到环境中的可能性降至最低。细菌细胞的死亡会导致处理水中的 DNA 释放，这可能会对 AR 转移到接收水体中存在的其他细菌造成风险。

       Urban wastewater treatment plants (UWTPs) are among the main hotspots of antibiotic resistance (AR) spread into the environment and the role of conventional and new disinfection processes as possible barrier to minimise the risk for AR transfer is presently under investigation. Accordingly, the aim of this work was to evaluate the effect of an advanced oxidation process (AOP) (specifically UV/H2O2) on AR transfer potential. UV/H2O2 disinfection experiments were carried out on real wastewater samples to evaluate the: i) inactivation of total coliforms, Escherichia coli and antibiotic resistant E. coli as well as ii) possible removal of target antibiotic resistance genes (ARGs) (namely, blaTEM, qnrS and tetW). In particular, DNA was extracted from both antibiotic resistant E. coli bacterial cells (intracellular DNA), grown on selective culture media, and the whole water suspension (total DNA) collected at different treatment times. Polymerase chain reaction (PCR) assay was performed to detect the absence/presence of the selected ARGs. Real Time quantitative Polymerase Chain Reaction (qPCR) was used to quantify the investigated ARGs in terms of copies mL− 1. In spite of the bacterial inactivation and a decrease of ARGs in intracellular DNA after 60 min treatment, UV/H2O2 process was not effective in ARGs removal from water suspension (total DNA). Particularly, an increase up to 3.7 × 103 copies mL− 1 (p > 0.05) of blaTEM gene was observed in total DNA after 240 min treatment, while no difference (p > 0.05) was found for qnrS gene between the initial (5.1 × 104 copies mL− 1) and the final sample (4.3 × 104 copies mL− 1). On the base of the achieved results, the investigated disinfection process may not be effective in minimising AR spread potential into the environment. The death of bacterial cells, which results in DNA release in the treated water, may pose a risk for AR transfer to other bacteria present in the receiving water body.

https://www.sciencedirect.com/science/article/abs/pii/S0048969716307276