喹诺酮信号分子和环丙沙星诱导铜绿假单胞菌对环丙沙星最低抑菌浓度影响的比较

Comparison of minimal inhibitory concentrations of ciprofloxacin against Pseudomonas aeruginosa induced by Pseudomonas quinolone signal and ciprofloxacin

目的探讨铜绿假单胞菌经喹诺酮信号分子(PQS)和环丙沙星2种诱导方案诱导后对环丙沙星最低抑菌浓度(MIC)的影响。方法收集临床分离的对环丙沙星敏感的铜绿假单胞菌,PQS以10,40,80μmol·L^(-1)3种诱导浓度共诱导5 d,环丙沙星以0.5×MIC,2×MIC和4×MIC 3种诱导浓度共诱导5 d,用琼脂倍比稀释法测定PQS和环丙沙星诱导前后环丙沙星的MIC值。同一诱导方案诱导前后对环丙沙星的MIC值用重复测量方差分析方法统计分析;2种诱导方案MIC值的比较用配对t检验。结果共得到12株对环丙沙星敏感的铜绿假单胞菌,其中包含1株质控菌。PQS的诱导浓度与诱导时间之间有交互作用(P<0.001),环丙沙星的诱导浓度与诱导时间之间有交互作用(P<0.05),2种诱导方案对环丙沙星MIC值的影响差异均有统计学意义(均P<0.05)。结论不同PQS诱导浓度下铜绿假单胞菌对环丙沙星MIC值随诱导时间的延长其变化的趋势不同;不同环丙沙星诱导浓度下MIC值随诱导时间的延长均呈增大的趋势,2种诱导方案对环丙沙星MIC值的影响不同。

Objective To investigate minimal inhibitory concentration（ MIC） of ciprofloxacin against Pseudomonas aeruginosa induced by Pseudomonas quinolone signal（ PQS） and ciprofloxacin in vitro. Methods Clinical isolates of Pseudomonas aeruginosa sensitive to ciprofloxacin were collected and then induced ciprofloxacin with three concentrations of0. 5 × MIC,2 × MIC and 4 × MIC,and PQS with three concentrations of10,40,80 μmol·L^-1,respectively for five days. The agar dilution method was used to measure MICs of all strains before and after inductions to ciprofloxacin. The MICs to ciprofloxacin before and after inductions of the same induction scheme were analysed by repeated measures analysis of variance and Paired t-test was used to compare the MICs of two induced schemes. Results Twelve clinical isolates of Pseudomonas aeruginosa sensitive to ciprofloxacin were obtained,among them one was used as the quality control strain included. There had interaction between induction time and induction concentrations of PQS or ciprofloxacin（ P〈0. 001 or P〈0. 05）. MICs of strains to ciprofloxacin of two induced schemes had statistically significant difference（ P〈0. 05）. Conclusion Under different concentrations of PQS,the trend of MIC values ofciprofloxacin to Pseudomonas aeruginosa varied by induction time. Under different concentrations of ciprofloxacin,MIC values tended to increase with the prolongation of induction time. The effects of two induction schemes on MIC of ciprofloxacin were different.