规模化猪场大肠杆菌β-内酰胺类药物耐药性检测及其超广谱β-内酰胺酶调查

摘要

为阐明我国规模化猪场大肠杆菌(E.coli)对抗菌药物的耐药现状和耐药机制,本研究于2006年2月至2008年12月从19个省市97个规模化猪场分离鉴定602株E.coli,进行了4大类16种抗菌药物耐药性检测和产超广谱β-内酰胺酶(ESBLs)菌株的筛选,采用PCR方法检测了9种常见β-内酰胺酶耐药基因,对产ESLBs菌株进行了脉冲电场凝胶电泳(PFGE)分析.结果显示:E.coli分离株对抗菌药物产生了不同程度的耐药性,602株E.coli中共有57株产ESBLs,产ESBLs菌株普遍耐受第二及第三代头孢药物.分别有35株和20株E.coli为blaCTX-M型和blaSHv型ESBLs,尚未发现blaOXA型和blaKPC型.PFGE结果显示,产ESBLs菌株间同源性低,推测我国猪源E.coli产ESBLs多为零星发生或以质粒介导的形式传播.本研究为了解我国猪源E.coli对β-内酰胺类药物的耐药现状和ESBLs变化趋势提供了实验依据.%To investigate the antibiotic resistance profiles and the molecular epidemiology of extended-spectrum (S -lactamase (ESBL)-producing E. Coli in China, a total of 602 E. Coli were isolated from 97 farms in 19 provinces from Feb 2006 to Dec 2008. All isolates were tested for susceptibility of antibiotics and identified for ESBL-producing. Susceptibility tests showed that all isolates were resistant to β -lactams in various degrees, of which 57 isolates were identified producing ESBLs and widespread resistant to the second and third generation of cephalosporins. Furthermore, PCR detections indicated that blaCTX-M-1-group and blaSHV were the predominant ESBL genes in the E. Coli isolates and no isolate carried blaOXA-23 or blaKPC genes. However, Pulsed-field gel electrophoresis analysis suggested that different mechanisms might be involved in the dissemination of the β -lactamases genes. To our knowledge, this is the first study on such a large-scale survey of epidemiology of p -lactams resistance in China.