摘要
      结合质粒转移是抗生素抗性基因（ARGs）传播的主要因素。然而，传统杀菌剂在结合质粒转移中的作用一直被忽视。基于越来越多地使用纳米和常规杀菌剂组合会导致联合污染的情况，本研究研究了常规杀菌剂普氯胺单独或与纳米CuO组合对磷酸缓冲盐水中大肠杆菌之间质粒RP4结合的影响。结果表明，50µg/L的普氯胺单独使用可使偶联转移显著增加1.82倍。100µg/L纳米CuO和普氯胺在5、50和500µg/L下的组合分别显著增加了2.56、3.61和2.13倍的结合。杀菌剂介导的ARGs偶联转移的促进主要归因于（i）细胞膜通透性的增加，（ii）通过增强细胞外聚合物中多糖的合成增加细胞粘附，以及（iii）与偶联、氧化应激、SOS反应、外膜、多糖输出相关的基因的上调，细胞间粘附和ATP合成。我们的研究结果为杀菌剂对ARGs转移的贡献提供了证据，这对控制ARGs传播的风险具有重要意义。
Abstract
Conjugative plasmid transfer is a major contributor to the spread of antibiotic resistance genes (ARGs). However, the role of conventional fungicides on conjugative plasmid transfer has been neglected. Based on the condition that the increasing use of the combination of nano- and conventional fungicides will lead to combined contamination, the effects of a conventional fungicide prochloraz alone or in combination with nano-CuO on the conjugation of plasmid RP4 between Escherichia coli in phosphate-buffered saline were investigated in this study. The results demonstrated that 50 µg/L prochloraz alone significantly increased the conjugative transfer by 1.82 folds. The combination of 100 µg/L nano-CuO and prochloraz at 5, 50, and 500 µg/L significantly increased the conjugation by 2.56, 3.61, and 2.13 folds, respectively. The promotion of conjugative transfer of ARGs mediated by fungicides is mainly attributed to (i) the increased cell membrane permeability, (ii) the increased cell adhesion via enhancing the synthesis of polysaccharides in extracellular polymeric substances, and (iii) the up-regulation of the genes relevant to conjugation, oxidative stress, SOS response, outer membrane, polysaccharide export, intercellular adhesion, and ATP synthesis. Our findings provide evidence for the contribution of fungicides to ARGs transfer, which is significant to control the risk of ARGs dissemination.

https://www.sciencedirect.com/science/article/abs/pii/S0304389421027308