摘要

    由抗生素抗性基因（ARGs）的水平转移介导的抗生素抗性的传播加剧了全球抗生素危机。目前，关于非抗生素，抗微生物（NAAM）化学品是否与环境中ARG的传播有关还知之甚少。在这项研究中，我们旨在评估普遍存在的NAAM化学物质三氯生（TCS）是否能够促进质粒携带的抗生素抗性基因（ARGs）的转化。通过使用携带氨苄青霉素抗性基因的质粒pUC19作为细胞外ARG，并使用模型微生物大肠杆菌DH5ɑ作为受体，我们发现，在环境检测浓度（0.2μg/ L至20μg/ L）下，TCS显着增强了质粒-的转化。可以将ARGs导入大肠杆菌DH5ɑ中达1.4倍。表型实验，全基因组RNA测序和蛋白质组学分析的结合表明，TCS暴露可将活性氧（ROS）的产生刺激1.3到1.5倍，诱导细菌膜损伤并上调外膜孔蛋白的翻译。此外，TCS增强了一般分泌系统Sec（1.4倍），双精氨酸转运系统Tat（1.2倍）和IV型菌毛分泌系统（2.5倍），这可能有助于菌毛对DNA的搜索/捕获。在一起，TCS可能会由于ROS过量产生，破坏细胞膜屏障，介导质粒的菌毛捕获和质粒通过细胞膜通道的转运而增加ARGs向大肠杆菌DH5α的转化频率。这项研究报告说，TCS可以在环境相关浓度下加速细胞外ARGs向感受态细菌的转化。这些发现提高了我们对生态系统中ARGs命运的理解，并呼吁对NAAM化学品传播抗生素耐药性进行风险评估。

    The dissemination of antibiotic resistance mediated by horizontal transfer of antibiotic resistance genes (ARGs) is exacerbating the global antibiotic crisis. Currently, little is known about whether non-antibiotic, anti-microbial (NAAM) chemicals are associated with the dissemination of ARGs in the environment. In this study, we aimed to evaluate whether a ubiquitous NAAM chemical, triclosan (TCS), is able to promote the transformation of plasmid-borne antibiotic resistance genes (ARGs). By using the plasmid pUC19 carrying ampicillin resistance genes as the extracellular ARG and a model microorganism Escherichia coli DH5ɑ as the recipient, we found that TCS at environmentally detected concentrations (0.2 μg/L to 20 μg/L) significantly enhanced the transformation of plasmid-borne ARGs into E. coli DH5ɑ for up to 1.4-fold. The combination of phenotypic experiments, genome-wide RNA sequencing and proteomic analyses revealed that TCS exposure stimulated the reactive oxygen species (ROS) production for 1.3- to 1.5-fold, induced bacterial membrane damage and up-regulated the translation of outer membrane porin. Moreover, general secretion system Sec (1.4-fold), twin arginine translocation system Tat (1.2-fold) and type IV pilus secretion systems (2.5-fold) were enhanced by TCS, which might contribute to the DNA searching/capture by pilus. Together, TCS might increase the transformation frequency of ARGs into E. coli DH5ɑ by ROS over-production, damaging cell membrane barrier, mediating the pilus capture of plasmid and the translocation of plasmid via cell membrane channels. This study reports that TCS could accelerate the transformation of extracellular ARGs to competent bacteria at environmentally relevant concentrations. The findings advance our understanding of the fate of ARGs in ecosystems and call for risk assessments of NAAM chemicals on disseminating antibiotic resistance.

    https://www.sciencedirect.com/science/article/abs/pii/S0048969720301315