多黏菌素B联合不同抗菌药物抗耐碳青霉烯肺炎克雷伯菌和大肠埃希菌的协同作用

Synergy of polymyxin B in combination with several antimicrobial agents in defencing carbapenems resistant Klebsiella pneumoniae and Escherichia coli

目的:观察多黏菌素B与几种抗菌药物联合抗耐碳青霉烯肺炎克雷伯菌和大肠埃希菌的协同作用。方法:16株碳青霉烯类耐药菌中肺炎克雷伯菌11株,大肠埃希菌5株,观察多黏菌素B与利福平、强力霉素、头孢吡肟、亚胺培南、头孢曲松和庆大霉素对上述菌株的协同作用,通过棋盘微量稀释法确定每种抗菌药物的最小抑菌浓度(MIC)值,根据MIC计算部分抑菌浓度指数(FICI),FICI<0.5定义为有协同作用。结果:试验菌株对除多黏菌素B、利福平和强力霉素外的抗菌药物均耐药。对于所有试验菌株,PB与RIF或DOX在生理浓度均存在协同作用,联合后PB的MIC值至少降低3倍以上。与其他研究药物的联合未观察到协同作用。结论:多黏菌素B与利福平、强力霉素体外联合抵御耐碳青霉烯大肠埃希菌和肺炎克雷伯菌存在协同作用。

Aim：To observe the synergy of polymyxin B in combination with several antimicrobial agents in defencing carbapenems resistant Klebsiella pneumoniae and Escherichia coli.Methods：Sixteen carbapenems resistant strains including 11 strains of Klebsiella pneumoniae and 5 strains of Escherichia coli were collected.The synergy of polymyxin B in combination with rifampin,doxycycline,cefepime,imipenem,ceftriaxone,or gentamicin in defencing the above-mentioned strains was observed.MIC of each antibiotic was determined by microdilution checkerboard tests,and the FIC index（FICI） was calculated by MIC.Synergy was defined as FICI0.5.Results： All strains were resistant to all of the tested antimicrobials with the exception of polymyxin B,rifampin and doxycycline.Synergy was observed in the combination of polymyxin B with rifampin and doxycycline in defencing all of the tested isolates,resulting in at least 3-fold decrease in MIC.No synergy was observed in other combinations studied at physiologic concentrations.Conclusion： Synergy exists in the combination of polymyxin B with rifampin and doxycycline in defencing carbapenems resistant Klebsiella pneumoniae and Escherichia coli.