摘要
      抗生素耐药基因（ARGs）的传播是一个全球性的公共安全问题，抑制其转移势在必行。在本研究中，开发了一种利用环境自由基暴露的新策略来抑制ARGs（RP4质粒）在水溶液中的偶联转移。长时间自由基（·OH、1O2和O2·−）暴露显著抑制了大肠杆菌（E.coli）菌株之间ARG的偶联转移频率，与1O2和O2·−相比，·OH更有可能攻击ARG，从而抑制偶联转移频率。与对照组相比，自由基暴露10分钟后，偶联转移频率从4.08×10−5显著降低到1.2×10−8，证实ARGs的转移和增殖受到了很好的抑制。相应地，自由基暴露10分钟后，转偶联物的数量显著减少了61.7%。自由基暴露10分钟后，观察到供体菌株中活性氧水平（ROS含量和酶水平）和DNA损伤诱导的反应显著降低。同时，细胞间的接触也通过抑制细胞外聚合物中多糖的合成而减弱。此外，由于三磷酸腺苷供应不足，质粒转移基因的表达在暴露10分钟后下调。本研究首次揭示了通过环境自由基暴露抑制ARGs转移和传播的潜在机制。
Abstract
Spread of antibiotic-resistant genes (ARGs) is a global public safety issue and inhibition their transfer is imperative. In this study, a novel strategy using environmental free radical exposure was developed to inhibit conjugative transfer of ARGs (RP4 plasmid) in aqueous solutions. Long-time free radical (·OH, 1O2, and O2·−) exposure significantly suppressed the conjugative transfer frequency of ARGs between Escherichia coli (E. coli) strains, and ·OH was more likely to attack ARG, thereby inhibiting the conjugate transfer frequency, compared to 1O2 and O2·−. Compared with the control, the conjugative transfer frequency significantly decreased from 4.08 × 10−5 to 1.2 × 10−8 after 10 min free radical exposure, confirming that the transfer and proliferation of ARGs were well inhibited. Correspondingly, the number of transconjugant significantly decreased by 61.7% after 10 min free radical exposure. Significant reductions in reactive oxygen species levels (ROS content and enzyme levels) and DNA damage-induced responses in the donor strains were observed after 10 min free radical exposure. Concurrently, intercellular contact was also weakened via inhibiting the synthesis of polysaccharides in extracellular polymeric substances. Moreover, the expressions of plasmid transfer genes were down-regulated after 10 min exposure due to the shortage of adenosine-triphosphate supply. This study firstly disclosed the underneath mechanisms for depressing ARGs transfer and dissemination via environmental free radical exposure.

https://www.sciencedirect.com/science/article/abs/pii/S0043135421011404