摘要

       使用点自来水和再生水中的抗生素抗性基因 (ARG) 丰度高于新鲜处理过的水中的抗生素抗性基因 (ARG)，这提出了一个问题，即分配系统中残留的消毒剂是否会促进 ARG 的传播。本研究调查了三种广泛使用的消毒剂（游离氯、氯胺和过氧化氢）促进 ARG 在大肠杆菌菌株内以及从大肠杆菌到鼠伤寒沙门氏菌属之间的转移。结果表明，这些消毒剂的亚抑制浓度（低于最小抑制浓度 [MIC]），即游离氯 0.1–1 mg/L Cl2、氯胺 0.1–1 mg/L Cl2 和 0.24–3 mg/L H2O2 ，与对照相比，导致属内结合转移的浓度依赖性增加分别为 3.4-6.4、1.9-7.5 和 1.4-5.4 倍。相比之下，与对照相比，属间接合频率略微增加了约 1.4-2.3 倍。然而，暴露于高于 MIC 的消毒剂浓度显着抑制了结合转移。这项研究为增强结合转移的可能潜在机制提供了证据和见解，其中涉及细胞内活性氧的形成、SOS 反应、细胞膜通透性增加和结合相关基因表达的改变。结果表明，某些氧化性化学物质，如消毒剂，会加速 ARGs 的转移，因此证明了评估用于控制抗生素耐药性的消毒替代方案的动机是合理的。这项研究还引发了有关环境化学品在抗生素耐药性全球传播中的潜在作用的问题。

       The greater abundances of antibiotic resistance genes (ARGs) in point-of-use tap and reclaimed water than that in freshly treated water raise the question whether residual disinfectants in distribution systems facilitate the spread of ARGs. This study investigated three widely used disinfectants (free chlorine, chloramine, and hydrogen peroxide) on promoting ARGs transfer within Escherichia coli strains and across genera from Escherichia coli to Salmonella typhimurium. The results demonstrated that subinhibitory concentrations (lower than minimum inhibitory concentrations [MICs]) of these disinfectants, namely 0.1–1 mg/L Cl2 for free chlorine, 0.1–1 mg/L Cl2 for chloramine, and 0.24–3 mg/L H2O2, led to concentration-dependent increases in intragenera conjugative transfer by 3.4–6.4, 1.9–7.5, and 1.4–5.4 folds compared with controls, respectively. By comparison, the intergenera conjugative frequencies were slightly increased by approximately 1.4–2.3 folds compared with controls. However, exposure to disinfectants concentrations higher than MICs significantly suppressed conjugative transfer. This study provided evidence and insights into possible underlying mechanisms for enhanced conjugative transfer, which involved intracellular reactive oxygen species formation, SOS response, increased cell membrane permeability, and altered expressions of conjugation-relevant genes. The results suggest that certain oxidative chemicals, such as disinfectants, accelerate ARGs transfer and therefore justify motivations in evaluating disinfection alternatives for controlling antibiotic resistance. This study also triggers questions regarding the potential role of environmental chemicals in the global spread of antibiotic resistance.

https://pubs.acs.org/doi/abs/10.1021/acs.est.6b03132