3种氟喹诺酮类药物对鲍曼不动杆菌的防耐药突变浓度研究

Contrast Analysis of Mutant Prevention Concentration of 3 Kinds of Fluoroquinolones to Acinetobacter Baumannii

目的研究3种氟喹诺酮类药物对临床分离的鲍曼不动杆菌敏感株及其环丙沙星诱导突变株的防耐药突变浓度(MPC),比较其防耐药突变能力。方法用环丙沙星琼脂平板筛选鲍曼不动杆菌临床分离株的突变株,用琼脂平板稀释法测定各实验菌株的最低抑菌浓度(MIC)和MPC。结果加替沙星和左氧氟沙星对临床分离株及其突变株的MPC低于环丙沙星。对临床分离株的MPC,加替沙星和左氧氟沙星均为0.25μg/m L,环丙沙星为2μg/m L;对突变株的MPC,加替沙星和左氧氟沙星为1～8μg/m L,环丙沙星为4～32μg/m L。结论对临床分离的鲍曼不动杆菌敏感株及其环丙沙星诱导的突变株,加替沙星和左氧氟沙星限制其耐药突变株的选择能力强于环丙沙星;对环丙沙星敏感的鲍曼不动杆菌的临床治疗,建议要避免这3种氟喹诺酮类的单药治疗。

Objective To measure the mutant prevention concentration（MPC） of fluoroquinolones to acinetobacter baumannii and its ciprofloxacin induced mutant strains. To evaluate the capacity of fluoroquinolones for restricting the selection of resistant mutant. Methods The mutant strains of acinetobacter baumannii separated from clinical sample were selected by ciprofloxacin. The minimum inhibition concentrations （MIC） and MPC of the fluoroquinolones for the clinical strain and mutant strains were determined by agar plates dilution method. Results MPC of gatifloxacin and levofloxacin were lower than those of ciprofioxacin for the clinical strain and its mutant strains. For the clinical strain, the MPC of gatifloxacin and levofloxacin were 0.25 μg/mL, MPC of ciprofloxacin was 2 μg/mL. For the mutant strains the MPC of gatifloxacin and levofloxacin were 1 - 8 μg/mL and 4 - 32 μg/mL, respectively. Conclusion The capacities of restricting selection of resistant mutant of gatifloxacin and levofloxacin were stronger than those of ciprofloxacin to acinetobacter baumannii and its ciprofloxacin induced mutant strains. But combined with pharmacokinetic parameters, it is proposed that using single one of these 3 fluoroquinolones in clinic should be avoided for treating acinetobacter baumannii sensitive to ciprofloxacin.