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目的 探讨铜绿假单胞菌(PA)临床分离株对碳青霉烯类抗生素耐药性与其产AmpCβ内酰胺酶(AmpC酶)的关系.方法 收集并鉴定PA临床分离株,采用头孢西丁敏感试验对产AmpC酶的菌株进行初筛.运用Kirby-Bauer纸片扩散法、固体培养基连续稀释法检测头孢菌素类与碳素霉烯类抗生素对PA筛选菌株的抗菌活性.采用三维确认试验检测碳青霉烯类抗生素耐药菌株产生AmpC酶的情况.结果 PA筛选菌株对头孢呋肟钠(CXM)、头孢噻甲羧肟(CAZ)、头孢噻肟钠(CTX)、头孢哌酮钠(CFP)及盐酸头孢吡肟(FEP)的耐药率分别为100%、36.3%、63.6%、54.5%、22.7%;对亚胺培南(IPM)、帕尼培南(ETP)、美罗培南(MEM)的耐药率分别为40.9%、45.0%、18.1%,部分菌株对所有试验用药均耐药.IPM、ETP、MEM对PA筛选菌株的最低抑菌浓度(MIC)均≥19 μg/ml,且各试药的最低杀菌浓度(MBC)值与MIC值相差较大,约36.0%菌株的MBC是MIC的16～32倍.约22.6%菌株检测出产生AmpC酶.结论 我市医院近半年来收集的PA对第4代头孢菌素类抗生素FEP具有较高的敏感性;对临床用碳青毒烯类抗生素MEM的敏感性明显高于IPM与ETP,但有较大比例的耐药菌株出现;部分菌株耐药性形成可能与其产生AmpC酶有关系.“,”Objective To study the change of sensitivity and resistance of Pseudomonas aeruginosa(PA)isolated from hospital to carbapenem antibitics.To investigate the relationship of the resistance to carbapenem antibitics with the production of AmpC enzyme.Methods PA isolated from our hospital was collected and identified.The strains producing AmpC enzyme were screened initially using sensitivity test of cefoxitin.Antibacterial actity of cephalosporins and carbapenem antibitics to PA was detected bv K-B and solid medium serial dilution test.Three-dimensionaI test was used to detect the production of AmpC enzyme of drug-resistant strains.Results The resistance rates of clinical isolates of PA to CXM,CAZ,CTX,CFP,FEP were 100%,36.3%,63.64%,54.5%,22.7%,respectively.The resistance rates of clinical isolates of PA to IPM,ETP,MEM were 28.64%,26.63%,18.1%,respectively.There was a wide gap between the results of MIC and MBC(MBC was 16-32 times as much as MIC in about 36.0%strains).AmpC enzyme from about 22.6%strains was detected.Conclusion PA has a higher sensitivity to generation 4 of eephalosporins.The sensitivity to MEM is significantly higher than of PA to IPM and ETP,but with a large umber of drug-resistant strains,which may be ralated to the production of AmpC enzyme in some strains.