6种氟喹诺酮类药物对凝固酶阴性葡萄球菌的防耐药变异浓度分析

目的 比较6种氟喹诺酮类药物对临床分离凝固酶阴性葡萄球菌耐药突变体的选择能力.方法 选择呼吸道标本,对苯唑西林、环丙沙星敏感的凝固酶阴性葡萄球菌34株,采用标准琼脂二倍稀释法、标准琼脂平板稀释法,测定6种氟喹诺酮类药物对凝固酶阴性葡萄球菌的最低抑菌浓度(MIC)、防耐药变异浓度(MPC).结果 MPC值比较,莫西沙星最低(MPC90为1 mg/L),左氧氟沙星和环丙沙星最高(MPC90均为32 mg/L).莫西沙星、卡屈沙星和加替沙星的MPC90/MIC90较低,均为2.结论 莫西沙星、卡屈沙星和加替沙星对凝固酶阴性葡萄球菌的MPC值较低,突变选择窗范围相对较窄.

Mutant prevention concentration of 6 kinds of fluoroquinolones for coagulase negative staphylococcus

Objective To determine the mutant prevention concentration （MPC of 6 kinds of fluoroquinolones for the clinical isolated coagulase negative staphylococcus, and to compare the 6 kinds of fluoroquinolones. Methods The minimal inhibitory concentrations （MIC） and the mutant prevention concentration （MPC） of ciprofloxacin, levofloxacin, gatifloxacin, cadrofloxacin, moxifloxacin and pazufloxacin were determined with 34 strains of coagulase negative staphylococcus isolated which were sensitive to oxacillin and ciprofloxacin by agar two-fold dilution method and ager plates dilution method. Results For MPCg0, moxifloxacin was the lowest （1 mg/L）. Cadrofloxacin, gatifloxacin and pazufloxacin, levofloxacin and ciprofloxacin were the highest among the 6 kinds of fluoroquinolones against coagulase negative staphylococcus which were 32 mg/L; as for MICgo/MPCgo, moxifloxacin, cadrofloxacin and gatifloxacin were lower; pazufloxaein, levofloxacin and eiprofloxacin were higher. The comparison of the pharmacokinetics parameter in vivo for the 6 kinds of fluoroquinolones against the 34 strains of coagulase negative staphylococcus showed that MPCgo was less than Cmax for moxifloxacin and cadrofloxacin, and was similar to gatifloxacin. Conclusion Moxifloxacin, cadrofloxacin and gatifloxacin have a lower MPC and narrower mutant selective window with a high ability to restrict the selection of eoagulase negative staphylococcus resistant mutants among the 6 kinds of fluoroquinolones against the coagulase negative staphylococcus.