大肠杆菌银离子耐受性机制研究进展

Research progress in silver ion tolerance mechanisms of Escherichia coli

摘要:

含银敷料、镀银涂层等医疗耗材与器械在临床治疗中的广泛应用，以及畜牧业饲料中抗菌剂和重金属剂的大量使用，增加了致病以及环境大肠杆菌对银离子的获得性耐受。为系统性了解大肠杆菌银离子耐受性机制，本文综述了大肠杆菌银离子耐受的复杂调控网络和多种生理机制，即调节外膜孔蛋白、能量代谢调节、外排系统的作用、运动性调节以及银离子还原能力。大肠杆菌通过缺失或突变外膜孔蛋白如OmpR、OmpC、OmpF等来减少银离子的内流；在高浓度银离子胁迫下，通过内源性的Cus系统和外源性的Sil系统提高银离子的外排能力；通过调节ArcA/B蛋白的表达来适应更高浓度的银离子环境。细菌的运动性也与银的耐受能力相关。此外，大肠杆菌还具还原银离子的能力，可降低银离子诱导的氧化应激。本文为理解细菌银离子耐受性的形成和传播提供了新的视角，并对下一代银基抗菌药物和疗法开发进行了展望。

Abstract:

Due to the wide application of silver-containing dressings and silver-coated medical devices in clinical treatment; the extensive use of antibacterial agents and heavy metal agents in feed factories, Escherichia coli has formed the tolerance to silver ions. To systematically understand the known silver ion resistance mechanisms of E. coli, this article reviews the complex regulatory network and various physiological mechanisms of silver ion tolerance in E. coli, including the regulation of outer membrane porins, energy metabolism modulation, the role of efflux systems, motility regulation, and silver ion reduction. E. coli reduces the influx of silver ions by missing or mutating outer membrane porins such as OmpR, OmpC, and OmpF. It adapts to high concentrations of silver ions by altering the expression of ArcA/B and enhances the efflux capacity of silver ions under high-concentration silver stress via the endogenous Cus system and exogenous Sil system. Furthermore, the motility of bacteria is related to silver tolerance. E. coli has the ability to reduce silver ions, thereby alleviating the oxidative stress induced by silver ions. These findings provide a new perspective for understanding the formation and spread of bacterial tolerance and provide directions for the development of next-generation silver-based antimicrobials and therapies.