摘要
      消毒副产物（DBPs）是水消毒的意外后果之一，通常在各种水环境中检测到。尽管已知DBP通过刺激染色体突变诱导抗微生物耐药性，但尚不清楚低浓度的DBP是否能刺激抗生素耐药性基因（ARGs）的偶联转移。本研究旨在研究两种典型的DBP，即三氯甲烷（TCM）和二氯乙腈（DCAN），对大肠杆菌属中RP4质粒的偶联转移的影响。研究结果表明，暴露于低浓度的中药和DCAN显著刺激ARGs的偶联转移，其中25μg/L的中药和10μg/L的DCAN在暴露16小时时分别导致约5.5倍和约6.0倍的最大倍数变化。此外，对潜在机制的评估揭示了细胞内活性氧生成、SOS反应、细胞膜通透性增加、与菌毛生成、ATP合成和RP4基因表达相关的基因和蛋白质表达上调的参与。我们的研究结果更好地了解了DBP在水环境中隐藏的生物效应和生态风险，特别是它们对抗生素耐药性传播的影响。
Abstract
Disinfection by-products (DBPs) are one of the unintended consequences of water disinfection that are commonly detected in various water environments. Although DBPs are known to induce antimicrobial resistance via stimulation of chromosomal mutations, it remains unclear whether low-concentration of DBPs could stimulate the conjugative transfer of antibiotic resistance genes (ARGs). The present study aimed to investigate the effect of two typical DBPs, namely trichloromethane (TCM) and dichloroacetonitrile (DCAN), on the conjugative transfer of RP4 plasmid in Escherichia coli genera. The results of the study demonstrated that exposure to low concentrations of TCM and DCAN significantly stimulated conjugative transfer of ARGs, wherein application of 25 μg/L of TCM and 10 μg/L of DCAN resulted in maximum fold change of ~5.5– and ~6.0–fold, respectively, at 16 h of exposure. Further, assessment of underlying mechanisms revealed the involvement of intracellular reactive oxygen species generation, SOS response, increase in cell membrane permeability, upregulation of expression of genes and proteins related to pilus generation, ATP synthesis, and RP4 gene expression. Our findings provided a better understanding of the hidden biological effects and the ecological risks of DBPs in the water environment, especially concerning their effect on the spread of antibiotic resistance.

https://www.sciencedirect.com/science/article/pii/S030438942102999X