摘要
目的研究普外科病区出现的4株碳青霉烯类药物耐药大肠埃希菌的分子流行病学特征及耐药机制。方法用K-B纸片法和琼脂稀释法进行药物敏感试验，三维酶抑制试验和EDTA—Na2协同试验分析酶的性质，通过脉冲场琼脂糖凝胶电泳（PFGE）分析耐药株的分子流行病学特征，特异性PCR及序列分析、接合试验、碱裂解法提取质粒和质粒转化试验研究碳青霉烯耐药的分子机制。结果4株大肠埃希菌对包括碳青霉烯在内的多种抗菌药物广泛耐药，PFGE显示4株分离株属于不同的克隆型，对碳青霉烯类药物的耐药主要由相对分子质量约56000的质粒携带的KPC-2基因介导，转化试验显示对氨基糖苷类和喹诺酮类药物的耐药性并未携带在同一质粒上。结论我院出现碳青霉烯耐药的大肠埃希菌，对碳青霉烯类药物的耐药主要由质粒介导的KPC-2基因引起。
Objective To study molecular epidemiology and carbapenem-resistance mechanism of four Escherichia coli strains isolated from general surgery wards. Methods Antibiotic susceptibility was carried out by K-B gar diffusion and agar dilution methods. Carbapenemases were screened by three dimensional test and EDTA-Na2-disk synergy test. Pulsed-field gel electrophoresis （PFGE） was performed to analyze molecular epidemiology of isolates. Plasmid was extracted by using an alkalinelysis technique. Conjunction experiment, transformation assay, specific PCR and DNA sequencing were performed to confirm carbapenemase genotype and its transmission mechanism. Results Four Escherichia coli isolates were resistant to most antimierobials including carbapenem. PFGE showed that the four isolates belong to four different clonal strains. Specific PCR and DNA sequence analysis identified that carbapenem resistance in four clinical isolates was mediated by KPC-2 encoded on an approximately 56 000 bp plasmid, and this plasmid did not harbor aminoglycosides and fluorquinolones resistant genes. Conclusion Four Escherichia coli isolates with carbapenem resistance are obtained from our hospital, and KPC-2 plasmid is main cause of carbapenem resistance in these isolates.
出处
《中华检验医学杂志》
CAS
CSCD
北大核心
2009年第10期1120-1123,共4页
Chinese Journal of Laboratory Medicine
基金
南京军区医药卫生十五重点课题（07M089）
关键词
大肠杆菌
卡巴配能类
Β内酰胺酶类
抗药性
细菌
Escherichia coli
Carbapenems
beta-Laetamases
Drug resistance, bacterial
