外膜蛋白对59株大肠埃希菌耐药性的影响

目的:研究外膜蛋白对59株耐头孢西丁大肠埃希菌耐药性的作用。方法:用聚合酶链反应(PCR)方法检测外膜蛋白OmpF基因;用聚丙烯酰胺凝胶电泳(SDS-PAGE)检测外膜蛋白;微量稀释法测定20种抗菌药物对试验菌株的敏感性。结果:59株大肠埃希菌中,29株OmpF基因阳性(49%),其中在产AmpC酶25株中有20株OmpF基因阳性;OmpF基因缺失的30株大肠埃希菌均未出现OmpF蛋白条带,其中13株同时缺失OmpC蛋白条带,29株OmpF基因阳性菌中有4株缺失OmpF蛋白条带;这59株菌对多种抗菌药物耐药。结论:OmpF基因及蛋白的缺失是非产AmpC酶菌对头孢西丁耐药的主要原因;孔蛋白缺失主要产生头孢西丁耐药,而对试验中的其它抗菌药物影响较小。

Effect of Outer Membrane Protein on Drug Resistance of 59 Strains of Escherichia Coli

OBJECTIVE：To investigate the effect of outer membrane protein on drug resistance of 59 strains of cefoxitin-resistant Escherichia coli.METHODS：PCR method was performed on test strains to identify OmpF gene.The outer membrane protein（OMP） profiles were studied by sodium dodecyl sulphate polyacrylamide gel electrophoresis（SDS-PAGE）.Sensitivity of 20 kinds of antibiotics to test strains was tested by Microdilution.RESULTS：Among 59 strains of Escherichia coli,OmpF gene were positive in 29 strains（49%）,of which 20 strains were among 25 strains which produced AmpC enzyme.30 OmpF gene-negative strains had not occurred OmpF protein bands,of which 13 strains missed OmpC protein bands simultaneously.Among 29 strains of OmpF gene-positive bacteria,4 stains missed OmpF protein bands.59 strains were all resistant to many types of antibiotics.CONCLUSION：Deletion of OmpF gene and protein is the main reason for non-AmpC enzyme production strains resistant to cefoxitin.Porin loss bring about primarily cefoxitin-resistant property but little impact on other antibiotics.