Efficacy of synergistic antibiotic combinations against KPC-2 carbapenemase producing Klebsiella pneumoniae strains / 中华检验医学杂志

ABSTRACT

Objective To investigate the synergistic efficacy of different antibiotic combinations against KPC-2 carbapenemase producing Klebsiella pneumoniae strains in vitro and search for effective antibiotic combination.Methods During 2008 - 2009,a total of 24 strains of K.pneumoniae producing KPC-2 carbapenemase were collected from 8 hospitals in the First Affiliated Hospital of Medical School of Zhejiang University,Ningbo LiHuiLi Hospital,Zhejiang People's Hospital,Hangzhou Third Hospital,the Second Hospital of Shaoxing,Hangzhou First Hospital,Fudan University Huashan Hospital,General Hospital of Nanjing Military Region.MLST technique was used for epidemiological analysis.The MIC of antibiotics,such as amikacin,minocycline,imipenem,amoxicillin/clavulanic-acid,ceftazidime,meropenem,gentamicin,cefoxitin,cefepime,rifampicin,polymyxinB,ciprofloxacin were determined by an agar dilution method,the MIC of tigecycline and piperacillin/tazobactain were determined by Etest.The antibacterial activities of cefepime in combination with amoxicillin/clavulanic-acid,amikacin,or ciprofloxacin,amikacin with ciprofloxacin,imipenem with amikacin,ciprofloxacin,polymyxinB,or minocycline,polymyxin B with rifampicin,ceftazidime with amoxicillin/clavulanic-acid were assessed by chequerboard synergy agar dilution tests against all the isolates.Results MLST showed 5 STs among 24 strains of KPC-2 carbapenemase producing K.pneumoniae,and the most prevalent clone was ST11 (15 strains).All isolates were susceptible to polymyxin B and tigecycline,and the resistance rate of minocycline was 4.2％.The synergetic effects were observed in cefepime-amoxicillin/clavulanic acid,imipenem-amikacin,ceftazidime-amoxicillin/clavulanic acid combinations as 19 isolates,13 isolates,and 13 isolates,respectively.Conclusions KPC-2 carbapenemase producing K.pneumoniae is sensitive to polymyxin B,tigecycline and minocycline.The synergetic effect is predominant in cefepime-amoxicillin/clavulanic acid,imipenem-amikacin ceftazidime-amoxicillin/clavulanic acid combinations in vitro,their clinical efficacy are worthy of further observation.