喹诺酮类和氨基糖苷类抗生素胁迫下外膜蛋白AhCirA对嗜水气单胞菌耐药性的影响

Effects of outer membrane protein AhCirA on antibiotic resistance of Aeromonas hydrophila under quinolone and aminoglycoside stress

摘要:

目的 外膜蛋白CirA作为特异性儿茶酚酸盐铁载体的转运通道，参与铁载体及其他营养物质的转运过程，在细菌生理功能中发挥着重要作用，但其对细菌耐药性的影响尚不明确。本研究探究ahcirA在抗生素胁迫下对嗜水气单胞菌ATCC 7966耐药机制的影响，为深入解析ahcirA调控细菌耐药性的分子机制提供理论基础。方法 以嗜水气单胞菌ATCC 7966为研究对象，构建ahcirA基因缺失株(ΔahcirA)，并测定其对多种喹诺酮类和氨基糖苷类抗生素的敏感性。进一步采用定量蛋白质组学技术，比较ΔahcirA菌株在有无抗生素胁迫条件下的蛋白表达差异，并通过生物信息学方法对差异表达蛋白进行功能分析。结果 在含恩诺沙星和诺氟沙星的培养基中ΔahcirA菌株的生长状况显著低于野生型菌株；而在含卡那霉素和链霉素的培养基中ΔahcirA菌株的生长状况优于野生型菌株。蛋白质组学与生物信息学分析表明，ahcirA缺失可能通过影响与小分子代谢过程等多种生物过程相关的蛋白及耐药基因的表达，从而改变细菌的耐药性。结论 外膜蛋白CirA在嗜水气单胞菌耐药性中具有重要作用，其缺失可通过调控多种功能蛋白及耐药基因的表达影响细菌对不同类型抗生素的敏感性。

Abstract:

Objective The outer membrane protein CirA serves as a specific transporter for catecholate-type siderophores and is involved in the uptake of siderophores and other nutrients, playing a crucial role in bacterial physiology. However, its impact on bacterial antibiotic resistance remains unclear. This study aimed to investigate the role of ahcirA in the antibiotic resistance of Aeromonas hydrophila ATCC 7966 under antibiotic stress, thereby providing a theoretical basis for elucidating the molecular mechanism by which ahcirA regulates bacterial resistance.Methods With A. hydrophila ATCC 7966 as the model organism, an ahcirA knockout strain (ΔahcirA) was constructed, and its susceptibility to multiple quinolones and aminoglycosides was assessed. Quantitative proteomics was further employed to compare protein expression profiles of ΔahcirA with and without antibiotic stress. Bioinformatic approaches were adopted for the functional analysis of differentially expressed proteins.Results In the media containing enrofloxacin and norfloxacin, the growth of ΔahcirA was significantly impaired compared with that of the wild-type strain. In contrast, ΔahcirA exhibited enhanced growth in the media supplemented with kanamycin and streptomycin. Proteomic and bioinformatic analyses revealed that the deletion of ahcirA may alter bacterial antibiotic resistance by affecting the expression of proteins involved in multiple biological processes, such as small molecule metabolism, and by modulating the expression of antibiotic resistance genes.Conclusion CirA plays a significant role in the antibiotic resistance of A. hydrophila. Its absence influences bacterial susceptibility to different classes of antibiotics by regulating the expression of diverse functional proteins and antibiotic resistance genes.