临床分离大肠埃希菌多重耐药菌株与外膜蛋白的相关研究

Study of the outer membrane proteins in multiple drug-resistant strains of Escherichia coli of clinical separation

目的了解临床分离大肠埃希菌对临床常用抗菌药物的耐药情况,并探讨其外膜蛋白与耐药性的相关性。方法收集2013年全年宁夏医科大学总医院及其分院患者标本中分离的大肠埃希菌共1058株,统计分析其标本来源和科室构成,纸片扩散法测定6种常用抗菌药物(头孢曲松、氨曲南、左氧氟沙星、环丙沙星、庆大霉素、阿米卡星)的药敏性,荧光定量PCR法检测Omp A、Omp F、Omp C m RNA表达水平,蛋白垂直电泳检测Omp A、Omp F和Omp C蛋白的表达水平。结果 1058株大肠埃希菌耐药情况为头孢曲松(67%)、环丙沙星(65.9%)、左氧氟沙星(61.9%)、庆大霉素(50.3%)、氨曲南(48.1%)、阿米卡星(3.7%)、单药耐药(31.0%)、双药耐药(30.9%)和多重耐药(27.9%),在多重耐药株中呈现Omp C m RNA和Omp C蛋白的高表达。结论大肠埃希菌外膜蛋白Omp C表达的强弱与细菌耐药有关,可能是导致细菌耐药的原因之一。

Objective To investigate antimicrobial resistance of clinically isolated Escherichia coli （E. coli）, and the relation of the outer membrane protein with drug resistance. Methods 1,058 strains orE. coli were isolated from patient specimens of General Hospital of Ningxia Medical University and the branches in 2013, and specimen sources and departments and then analyzed by statistical analysis. Additionally, analyzing the antimicrobial susceptibility of 6 ordinary antibiotics including ceflriaxone, aztreonam, ofloxacin, ciprofloxacin, gentamycin and amikacin. Then, mRNA of OmpA, OmpF, OmpC were detected by Real-time PCR; protein expression of OmpA, OmpF and OmpC were explored by protein electrophoresis. Results There were 1,058 E. coli antimicrobial susceptibility tests showed that resistance rate ofE. coli to ceflriaxone, ciprofloxacin, levofloxacin and gentamicin were over 50%, including ceftriaxone（67%）, ciprofloxacin（65.9%）, levofloxacin（61.9%）, gentamicin（50.3%）, respectively. Moreover, the resistance rate to aztreonam and amikacin were 48.1% and 3.7%, and the positive rate of mono-resistance E. coli was 31.0%, double-resistance was 30.9% and multi-drug resistance was 27.9%. Finally, OmpC mRNA and OmpC protein were highly expressed in multi-drug resistant bacteria. Conclusion Expression of OmpC protein is closely related with drug resistance, which may be directly involved in the mechanism of bacterial resistance.