铜绿假单胞菌临床分离株对喹诺酮类药物的耐药性研究

Study on the resistance to quinolone of clinical isolated Pseudomons aeruginosa

目的 :对铜绿假单胞菌的耐药性进行调查并研究药物联用后对铜绿假单胞菌 MIC的逆转情况。方法 :通过琼脂二倍稀释法检测 86株铜绿假单胞菌对四种喹诺酮类药物与利舍平及维拉帕米联用前后的MIC值及 86株铜绿假单胞菌对其它常用抗生素的 MIC值 ;用微量棋盘稀释法测得氧氟沙星、环丙沙星与头孢他啶、哌拉西林联合作用后的部分抑菌浓度 (FIC)指数。结果 :86株铜绿假单胞菌对诺氟沙星耐药率为74.4% ;氧氟沙星的耐药率为 5 2 .2 % ;环丙沙星耐药率为 15 .1% ;洛美沙星耐药率为 2 0 .9%。加入利舍平及维拉帕米后四种喹诺酮类药物对大部分菌株的 MIC值均无变化 ,氧氟沙星和环丙沙星与头孢他啶、哌拉西林联用后 FIC指数范围为 0 .1～ 1.5 ,6 6 %的 FIC指数≤ 0 .5。结论 :86株铜绿假单胞菌除对四种喹诺酮类药物呈现交叉耐药外 ,还对大多数临床常用的抗生素耐药。利舍平及维拉帕米不能使诺氟沙星、氧氟沙星、环丙沙星、洛美沙星的耐药性降低。氧氟沙星和环丙沙星与头孢他啶、哌拉西林联用有相加或协同作用 ,抗菌活性明显增强。

Objective: To investigate the resistance and the bactericidal activity of Pseudomonas to quinolone and quinolone combined with other drugs. Method: Using the method of agar dilution to measure the MIC of 86 strains clinically isolated Pseudomons aeruginosa with four kinds of quinolone individually and combined with reserpine and verapamil. The method of microdilution checkerboard techniques in used to determine the fractional inhibitory concentration (FIC) index of ofloxacin or ciprofloxcin combined with ceftazidime or piperacillin. Results: Of all the 86 strains of Pseudomons aeruginosa , the resistant rate to norfloxcin is 74.4%, 52.2% to ofloxacin; 15.1% to ciprofloxacin and 20.9% to lomefloxacin. The MIC of most of the strains has no changes for 4 kinds of quinolone combined with reserpine and verapamil. The range of FIC index of the combination of 4 kinds of quinolones with ceftazidime or piperacillin is 0.1~1.5, 66% FIC index is ≤0.5. Conclusion: The 86 strains of Pseudomons aeruginosa show cross resistance not only to 4 kinds of quinlolnes, but also to most of the antibiotics those are used frequently and heavily in clinic, especially β lactam and aminoglycoside. After adding reserpine and verapamil, the MIC to 4 kinds of quinolone of most of the strains has no changes. That means reserpine and verapamil can′t reduce the resistance of Pseudomons aeruginosa to norfloxcin, ofloxacin, ciprofloxcin or lomefloxcin. Combination of ofloxacin or ciprofloxcin with ceftazdime of pipercillin has the effect of addition or synergy, and the bactericidal activity incresases distinctively.