左氧氟沙星联合头孢哌酮舒巴坦对大肠埃希菌和铜绿假单胞菌突变选择窗的影响

Effects of levofloxacin combined with cefoperazone sulbactam on mutant selection window of E.coli and P.aeruginosa

目的：在体外研究左氧沙星（LVX）联用头孢哌酮舒巴坦（SCF）对大肠埃希菌和铜绿假单胞菌突变选择窗（MSW）的影响，为防止细菌耐药的产生提供理论依据。方法：采用琼脂二倍稀释法，测定LVX与SCF单用及联用时，对临床分离10株大肠埃希菌和10株铜绿假单胞菌的最低抑菌浓度（MIC）和防耐药突变浓度（MPC），计算选择指数（SI=MPC／MIC）。结果：LVX单用时，LVX对大肠埃希菌和铜绿假单胞菌的SI值分别为16-32和16-64，LVX和SCF联用时，LVX对大肠埃希菌和铜绿假单胞菌的s1值分别为4-32和8-32。两药联合使用后LVX对大肠埃希菌和铜绿假单胞菌的sI值显著低于LVX单用（x2=15．41，P〈O．05；x2=11．88，P〈0.05）。结论：LVX与SCF联合使用可降低LVX单用对大肠埃希菌和铜绿假单胞菌MPC，缩小MSW，减少耐药菌产生。

OBJECTIVE To study whether the combination of levofloxacin and cefoperazone sulbactam could influence on mutant selection window of E. coli and P. aeruginosa in vitro. METHODS MPC of the two drugs for 10 strains E. coli and 10strains P. aeruginosa were detected with agar dilution method, the mutantal selection index（SI = MPC/MIC） were calculated. RESULTS The SI of levofloxacin alone for 10 strains of E. coli and 10 strains P. aeruginosa were 16 - 32,16 - 64, respective- ly. The SI of the combination were 4 - 32, 8 - 32, respectively. SI of levofloxacin combined with cefoperazone suihactam against E. coli and P. aeruginosa were also lower than the single application of levofloxacin（ X2 = 15.41, P〈0. 05; x2 = 11.88, P〈0. 05）. CONCLUSION The combination of levofloxacin and cefoperazone sulbactam can decrease MPC of levofloxacin a lone against E. coli and P. aeruginosa, and narrow the MSW. The emergence of resistant strains was decreased.