耐亚胺培南铜绿假单胞菌的耐药特征及其耐药机制研究

Study on antimicrobial resistance characteristics and mechanism of imipenem-resistant Pseudomonas aeruginosa

目的分析耐亚胺培南铜绿假单胞菌对常用抗菌药物的耐药特征,并研究对亚胺培南的耐药机制。方法采用Micro-Walkaway-40进行细菌鉴定和药物敏感试验,应用PCR法对铜绿假单胞菌亚胺培南耐药相关基因(IMP、VIM、GIM、OXA)和膜微孔蛋白基因oprD2进行检测,琼脂稀释法检测氰氯苯腙(cccp)对耐亚胺培南铜绿假单胞菌MIC的影响。结果 65株耐亚胺培南铜绿假单胞菌对舒普深、特治星、阿米卡星的耐药率分别为38.5%、43.1%和44.6%,对头孢他啶、马斯平和环丙沙星的耐药率分别为50.8%、53.8%和55.4%;65株耐亚胺培南铜绿假单胞菌中,IMP阳性11株(16.9%)、VIM 4株(6.2%),oprD2基因缺失5株(7.7%),其余耐药基因未检出;CCCP检测阳性时,亚胺培南的MIC值下降,提示存在主动外排机制的菌株7株(10.8%)。结论耐亚胺培南铜绿假单胞菌多重耐药现象较为严重,其耐药机制主要与细菌产IMP型金属β-内酰胺酶、细胞主动外排机制以及膜微孔蛋白基因oprD2缺失有关。

Objective To investigate the antimicrobial resistance characteristics and the mechanisms of imipenem-resistance of Pseudomonas aeruginosa producing carbapenemase.Methods Sixty five strains from patients were identified and drug susceptibility test was performed by Micro-Walkaway-40 automatic microbial analysis system.The susceptibility of cefoperazone/sulbactam was performed by KB method.The resistant genes of Pseudomonas aeruginosa isolates,including IMP,VIM,GIM,SM,GS,OXA and oprD2,were detected by PCR.The influence of active efflux inhibitors carbonyl cyanide chlorophenylhydrazone（CCCP） on minimal inhibitory concentration（MIC） of both standard Pseudomonas aeruginosa and Imipenem-resistant Pseudomonas aeruginosa to ciprofloxacin,enrofloxacin and tetracycline were measured by agar dilution method.Results The resistance rate of imipenem-resistance Pseudomonas aeruginosa isolates to cefoperazone sulbactam（Sulperazone）,piperacillinl tazobactam（Tazocin）,amikacin,ceftazidime,cefepime（Maxipime） and ciprofloxacin was 38.5%,43.1%,44.6%,50.8%,53.8% and 55.4%,respectively.Out of sixty five strains,11were positive for IMP gene（16.9%）,4 for VIM（6.2%）,5 for oprD2（7.7%）.CCCP had distinct effect on resistance strains MIC to ciprofloxacin and enrofloxacin,and seven strains were positive（10.8%）.Conclusion The P.aeruginosa isolates with imipenem-resistance shows seriou multidrug-resistance.It was the major antimicrobial merchanisms that the metallo-beta-lactamase producing of IMP,efflux pump and loss of oprD2 gene led to PA resistant to cephalosporins and carbapenems in Jiaodong district.