Bacteria are continually challenged with variety of synthetic chemicals/xenobiotics in their immediate surroundings, including pesticides. Chlorpyrifos (CP) is one of the most commonly used organophosphate pesticides in the world. The non-environmental strain of Escherichia coli, BL21 (DE3) displayed high tolerance to chlorpyrifos but with no/negligible degradation. The intrinsic resistance mechanisms that aid the organism in its high tolerance were probed. Efflux pumps being ubiquitous in nature and capable of conferring resistance against wide variety of xenobiotics were probes and was found to be over-expressed in CP stress. Also, an efflux pump inhibitor PAβN increased the susceptibility of E. coli to the pesticide due to the intracellular accumulation of CP. The tripartite efflux pump EmrAB-TolC with increased expression in both transcript and protein on CP exposure, might play a major role in CP tolerance. The transcriptional regulators involved in multidrug resistance along with transporters belonging to all the major families conferring antimicrobial resistance were up-regulated. Also up-regulated were the genes involved in phopshonate metabolism, and all the genes in the copper or silver export system. The common resistance mechanisms i.e, activation of efflux pumps between CP, antibacterial metals and antibiotics resistance could result in cross-resistance, ultimately increasing the prevalence of multidrug resistant strains, making infections hard to treat.

中文翻译：

---

外排介导的大肠埃希菌对毒死rif的耐受性BL21（DE3）

细菌在其周围环境中不断受到各种合成化学物质/异生物素的挑战，包括农药。毒死rif（CP）是世界上最常用的有机磷酸盐农药之一。大肠杆菌的非环境菌株BL21（DE3）对毒死rif具有很高的耐受性，但降解没有/可以忽略不计。探索了有助于有机体高耐受性的内在抗性机制。自然界中普遍存在并且能够赋予对多种异种生物素的抗性的外排泵是探针，并且发现在CP应激中过表达。而且，由于CP的细胞内积累，外排泵抑制剂PAβN增加了大肠杆菌对农药的敏感性。在CP暴露下转录和蛋白质表达均增加的三方外排泵EmrAB-TolC可能在CP耐受中起主要作用。涉及多药耐药性的转录调节因子以及所有赋予抗菌素耐药性的主要家族的转运蛋白均被上调。磷酸膦酸酯代谢相关的基因以及铜或银输出系统中的所有基因也被上调。常见的耐药机制，即CP之间的外排泵激活，抗菌金属和抗生素耐药性可能导致交叉耐药，最终增加了多药耐药菌株的流行，使感染难以治疗。涉及多药耐药性的转录调节因子以及所有赋予抗菌素耐药性的主要家族的转运蛋白均被上调。磷酸膦酸酯代谢相关的基因以及铜或银输出系统中的所有基因也被上调。常见的耐药机制，即CP之间的外排泵激活，抗菌金属和抗生素耐药性可能导致交叉耐药，最终增加了多药耐药菌株的流行，使感染难以治疗。涉及多药耐药性的转录调节因子以及所有赋予抗菌素耐药性的主要家族的转运蛋白均被上调。磷酸膦酸酯代谢相关的基因以及铜或银输出系统中的所有基因也被上调。常见的耐药机制，即CP之间的外排泵激活，抗菌金属和抗生素耐药性可能导致交叉耐药，最终增加了多药耐药菌株的流行，使感染难以治疗。