铜绿假单胞菌的临床分布及对环丙沙星耐药机制的研究

摘要

Objective To analyze the clinical distribution and drug resistance of pseudomonas aeruginosa (PAE), and explore the drug resistance mechanisms of ciprofloxacin-resistant of PAE.Methods 287 strains of PAE were col-lected from the hospital patients from Sep 2012 to Sep 2013.Drug resistance testing were performed by K-B disk diffu-sion method,and minimal inhibitory concentrations (MICs)of ciprofloxacin to PAE were determined by broth micro-di-lution method.Genes gyrA,gyrB,parC and parE of PAE were amplified by PCR,then the PCR products were se-quenced to identify the mutations in these genes.Results 76.3% P.aeruginosa were isolated from sputum,PAE infec-tion were mostly occurred in ICU (29.3%)and following by department of respiratory diseases (22.6%);PAE had a high susceptibility to piperacillin/tazobactam and imipenem,the sensitive rate were over 70.0%;While PAE had the highest resistant rate to ampicillin (97.9%),following by ciprofloxacin (44.9%).Among the 45 PAE isolates (MIC of ciprofloxacin≥32μg/ml ),gyrA gene mutations were found in 42 strains,and double mutations of gyrA and parC genes were found in 28 strains.Conclusion Pseudomonas aeruginosa is multi-drug resistance,mutation of gyrA gene is one if the main resistant mechanisms of PAE to ciprofloxacin.It’s necessary to reinforce the monitoring on clinical distribu-tion and drug resistance of PAE,to guide the rational clinical drug usage and control the emergence of drug resistant strains.%目的：分析医院铜绿假单胞菌（PAE）的临床分布和耐药性，并了解其对环丙沙星的耐药机制。方法我院2011年9月-2013年9月收集的287株铜绿假单胞菌。采用琼脂纸片扩散法（K-B法）进行药敏试验，微量肉汤稀释法测定环丙沙星对PAE的最低抑菌浓度（MIC）。应用PCR方法扩增PAE的 gyrA、gyrB、parC及 parE基因，并测序来确定基因的突变。结果287株铜绿假单胞菌以痰液标本中分离最多（76．3％）；主要感染分布在重症监护室（29．3％）和呼吸内科（22．6％）；且对哌拉西林/他唑巴坦及亚胺培南敏感，敏感率均在70％以上；而对氨苄西林及环丙沙星耐药率高，分别达97．9％和44．9％。在45株（环丙沙星 MICs≥32μg/ml）铜绿假单胞菌中，有42株均存在 gyrA基因突变，且28株存在着 gyrA基因和 parC基因双突变。结论铜绿假单胞菌多重耐药现象严重，gyrA基因突变是PAE对环丙沙星耐药的主要机制之一。应加强对铜绿假单胞菌的临床分布及耐药性监测，更好地指导临床合理用药，控制医院感染。