摘要

    在消毒前后，分别从两家医院和两家市政废水处理厂（WWTP）的废水中调查了抗生素抗性细菌（ARB）和抗生素抗性基因（ARG）。网络分析结果表明，已鉴定出8个属是ARGs的主要潜在宿主，包括分枝杆菌属，费氏杆菌属，嗜热单胞菌，摩根氏菌，肠球菌，拟杆菌，Myroides和Romboutsia。在污水处理厂中，通过氯或紫外线（UV）消毒可以同步且一致地去除ARG及其可能的细菌宿主。揭示了通过紫外线，氯和协同的紫外线/氯消毒去除ARB和ARGs以及共轭转移RP4质粒的机理。与单独的紫外线相比，UV /氯组合（8 mJ / cm2，氯2 mg / L）可改善ARB的失活1.4 log，并有效地克服了光活化。但是，ARGs的降解要比ARB灭活更困难。直到紫外线剂量增加到320 mJ / cm2，ARG的对数去除率为0.58-1.60。同时，当2 mg / L的氯与UV结合时，ARG的去除率提高了1–1.5 log。在紫外线辐射期间添加低剂量氯（1-2 mg / L）的协同作用可以有效地同时改善ARB和ARGs的去除。在水平基因转移（HGT）中也发生了相同的协同作用。非致死剂量氯（0.5 mg / L）增加了结合转移频率，这证实IV型分泌系统（T4SS）蛋白vir4D，vir5B和vir10B的mRNA表达水平显着提高。紫外线/氯（紫外线≥4 mJ / cm2，氯≥1 mg / L）可显着降低RP4质粒偶联转移的风险。这些发现可能对评估和控制ARGs在环境中转移和传播的风险具有重要意义。

    Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) were investigated from effluent of two hospital and two municipal wastewater treatment plants (WWTPs) before and after disinfection. The results of network analysis showed that 8 genera were identified to be the main potential hosts of ARGs, including Mycobacterium, Ferruginibacter, Thermomonas, Morganella, Enterococcus, Bacteroides, Myroides and Romboutsia. The removal of ARGs and their possible bacterialhosts were synchronous and consistent by chlorine or ultraviolet (UV) disinfection in WWTPs. The mechanisms of ARB and ARGs removal, and conjugation transfer of RP4 plasmids by UV, chlorine and synergistic UV/chlorine disinfection was revealed. Compared to UV alone, ARB inactivation was improved 1.4 log and photoreactivation was overcomeeffectively by UV/chlorine combination (8 mJ/cm2, chlorine 2 mg/L). However, ARGs degradation was more difficult than ARB inactivation. Until UV dosage enhanced to 320 mJ/cm2, ARGs achieved 0.58–1.60 log removal. Meanwhile, when 2 mg/L of chlorine was combined with UV combination, ARGs removal enhanced 1–1.5 log. The synergistic effect of adding low-dose chlorine (1–2 mg/L) during UV radiation effectively improved ARB and ARGs removal simultaneously. The same synergistic effect also occurred in the horizontal gene transfer (HGT). Non-lethal dose chlorine (0.5 mg/L) increased the conjugation transfer frequency,which confirmed that the mRNA expression levels of type IV secretion system (T4SS) proteins vir4D, vir5B and vir10B were significantly enhanced. The risk of RP4 plasmid conjugation transfer was significantly reduced with UV/chlorine (UV ≥ 4 mJ/cm2, chlorine ≥ 1 mg/L). These findings may serve as valuable implications for assessing and controlling the risk of ARGs transfer and propagation in the environment.

    https://www.sciencedirect.com/science/article/abs/pii/S0043135420308265