【摘要】 目的确定Cpx系统对细菌致死性应激的影响,探讨该系统在抗生素耐药中的作用。方法测定在不同杀菌机制抗生素处理后野生菌及其突变菌的最小抑菌浓度(minimal inhibitory concentration,MIC),确定抗生素对细菌存活率的影响。使用real-time PCR确定在奥索利酸(Oxolinic acid)作用大肠杆菌BW25113及其Cpx系统基因突变菌时,katG、katE、ahpC、sodA、sodB基因表达水平的改变以及使用酶标仪检测对活性氧族ROS生成的改变。结果在不同抗生素的处理下突变菌Δcpx A、Δcpx P、ΔcpxR的存活率有明显提高,与ROS生成有关的基因均有不同程度的上调,过氧化氢生成增加,羟自由基的生成减少。结论 Cpx系统介导的细菌的抗生素耐药与ROS相关。更多还原

【Abstract】 Objective To determine the effect of Cpx system on bacteria lethal stress and explore its effects on antibiotic resistance. Methods The MIC different bactericidal mechanisms antibiotic treat on Escherichia coli BW25113 and its Cpx mutant strain were measured,the effect of antibiotic on bacteria survival was determined. katG,katE,ahpC,sodA,sodB gene expression changes during oxolinic acids’ killing on Escherichia coli BW25113 and its mutant strain were studied by using real-time PCR. The amount of reactive oxygen species( ROS)generated was detected by using probes. Results Bacterial survival was significantly increased after exposed to different antibiotics in E. coli mutants Δcpx A,Δcpx P,ΔcpxR. Genes related to ROS were up-regulated differently. The generated amount of hydrogen peroxide was increased,the generated amount of hydroxyl free radicals was decreased. Conclusion The Cpx system mediated bacterial antibiotic resistance is related to ROS.更多还原