论文部分内容阅读
目的探讨广州地区铜绿假单胞菌对喹诺酮类药物的耐药机制。方法对喹诺酮耐药株的gyrA和parC基因进行限制性片段长度多态性分析(PCR-RFLP),并对其中的高水平耐药株gyrB和parE基因进行测序;用琼脂稀释法测定加入碳酰氰基-对-氯苯腙(CCCP)前后环丙沙星的最小抑菌浓度(MIC);同时用SDS-PAGE对高水平耐药株的外膜蛋白进行电泳分析。结果有72.7%(72/99)的菌株发生gyrA突变,主要为Thr-83-Ile;25.3%(25/99)的菌株发生parC突变,主要为Ser-87-Leu,且均是gyrA和parC双基因突变;gyrB和parE突变较少见。53.3%(53/99)的菌株的MIC可被CCCP逆转,其MIC能明显降低;7%(7/10)的高水平耐药株的外膜蛋白在43～67kDa间条带增多,其蛋白含量有差异。结论抗菌药物作用靶位的改变和外排泵机制是本地区铜绿假单胞菌对喹诺酮类耐药的重要机制。
Objective To investigate the mechanism of resistance to quinolones in Pseudomonas aeruginosa in Guangzhou. Methods The gyrA and parC genes of quinolone-resistant isolates were analyzed by restriction fragment length polymorphism (PCR-RFLP), and the high-level resistant strains gyrB and parE were sequenced. Agar dilution The minimum inhibitory concentration (MIC) of ciprofloxacin before and after cyano-p-chlorophenylhydrazone (CCCP) was determined. The outer membrane proteins of high-level drug-resistant strains were analyzed by SDS-PAGE. RESULTS: 72.7% (72/99) of the strains had gyrA mutation, mainly Thr-83-Ile; 25.3% (25/99) of the strains had parC mutation, mainly Ser-87-Leu, and all were gyrA and parC Double gene mutations; gyrB and parE mutations are rare. The MICs of 53.3% (53/99) strains were reversed by CCCP and their MICs were significantly reduced. The outer membrane proteins of 7% (7/10) high-resistant strains increased in 43-67 kDa bands, and their proteins There are differences in content. Conclusion The change of target site of antimicrobial agents and efflux pump mechanism are important mechanisms of quinolones resistance in Pseudomonas aeruginosa.