2006-2008年大肠埃希菌耐药基因的研究

Study on drug resistant genes in Escherichia coli during 2006-2008

目的了解耐药大肠埃希菌多药耐药机制的时间变化趋势。方法收集南京医科大学第一附属医院2006年3月-2008年11月患者尿液标本中分离的大肠埃希菌共60株,采用聚合酶链反应检测多种耐药基因,利用SPSS统计软件进行指标和样本聚类分析。结果除对亚胺培南敏感外,耐药大肠埃希菌对多种抗菌药物耐药;β-酰胺类耐药基因、氨基糖苷类耐药基因、喹诺酮类耐药基因和基因突变、消毒剂和灭菌剂相关基因、可移动元件遗传标记基因均有检出;2007年大多耐药基因检出率低于其他两年;qacE△1和intI1存在时间上的差异(P=0.045),2008年的检出率是最高的;3年间膜孔蛋白突变率、teha和mdfa检出率均为100.0%;聚类分析发现intI1和qacE△1、tnp513和ISCR1相对稳定,但质粒traA、trbC和插入序列IS26、ISEcp1的位置不固定;2008年菌株的同源性更明显。结论耐药基因时间变化特征不明显,但耐药机制同可移动遗传元件紧密相关。

OBJECTIVE To investigate the time change of drug resistant genes about Escherichia coli. METHODS A total of 60 strains of E.coli were collected from First Affiliated Hospital of Nanjing Medical University during Mar 2006-Nov 2008.They were detected by polymerase chain reaction about drug resistant genes.Variable cluster and sample cluster were performed by the use of SPSS statistical software. RESULTS Among 60 strains,there were multiply drug resistant except for imipenem.Many drug resistant mechanisms were found,including β-lactam resistance genes,aminoglycoside resistance genes and gene mutations in quinolone resistance gene,disinfectants related genes and mobile elements.The detective rate in 2007 was lower than others in 2006 and 2008.Only QacE △ 1 and intI1 were statistically significant in the time tendency（P=0.045）.The mutation rate of membrane pore protein,and the detective rates of teha and mdfa were 100.0%.Cluster analysis showed the stability of intI1 and qacE△1（tnp513 and ISCR1）,and variability of plasmid traA,trbC and insertion sequence IS26,ISEcp1.Higher homology was found among the stains in 2008. CONCLUSION The time variation of resistance genes is not obvious,but the mechanism of resistance is closely related to mobile genetic elements.