耐亚胺培南铜绿假单胞菌耐药特征及其耐药机制的初步研究

摘要

目的：分析临床分离的耐亚胺培南铜绿假单胞菌对常用抗菌药物的耐药特征及对亚胺培南的耐药机制。方法采用 BD Phoenix 100全自动微生物分析仪进行细菌鉴定，纸片扩散法（K-B 法）进行药敏试验；聚合酶链反应（PCR）检测碳青霉烯酶相关基因（IMP 、VIM 、OXA、GES）及外膜蛋白基因 oprD2。结果耐亚胺培南铜绿假单胞菌对阿米卡星耐药率最低，为8．33％；对庆大霉素、妥布霉素的耐药率＜20％；第三四代头孢菌素、氨曲南、美罗培南、复方磺胺甲口恶唑、米诺环素等抗菌药物抗菌活性差，耐药率＞60％，对氨苄西林/舒巴坦全部耐药。检测到1株 OXA-17阳性菌，阳性率2．78％；oprD2缺失率为38．89％；未检测到其余耐药基因。结论耐亚胺培南铜绿假单胞菌除对氨基糖苷类抗生素耐药率较低外，对其他常用抗菌药物耐药严重；膜蛋白 OprD2缺失与碳青霉烯酶产生等机制导致铜绿假单胞菌对亚胺培南耐药。%Objective To investigate antimicrobial resistance characteristics and mechanisms of imipenem-resistant Pseudomonas aeruginosa (P .aeruginosa)isolated from clinical specimens.Methods Bacterial strains were identi-fied by BD Phoenix 100 automatic microbial analysis system,antimicrobial susceptibility testing was performed by Kirby-Bauer method;Carbapenemase genes (IMP ,VIM ,OXA,GES )and outer membrane protein gene oprD2 were detected by polymerase chain reaction.Results Resistant rates of imipenem-resistant P .aeruginosa strains to ami-kacin was the lowest (8.33%);resistant rates to gentamicin and tobramycin were<20%;resistant rates to the third and fourth generation cephalosporins,aztreonam,meropenem,compound sulfamethoxazole and minocycline were all>60%,and all strains were resistant to ampicillin/sulbactam.The positive rate of OXA-17 gene was 2.78%(n=1 ),deletion rate of oprD2 was 38.89%,the other drug-resistant genes were not detected.Conclusion Except aminoglycosides,resistance of imipenem-resistant P .aeruginosa to other antimicrobial agents is serious;resistance of P .aeruginosa to imipenem may be due to lacking of OprD2 and production of carbapenemases.