广西畜禽大肠杆菌O157∶H7流行病学调查

Epidemiologic survey on Escherichia coli O157∶H7 isolated from domestic animals and domestic birds in Guangxi

目的为了掌握广西畜禽大肠杆菌O157∶H7的流行病学情况。方法应用细菌分离、生化特性鉴定、血清凝集反应和PCR鉴定等方法在2007-2010年广西200多个畜禽养殖场进行畜禽大肠杆菌O157∶H7的流行病学调查。对采集的2 915份样本进行了大肠杆菌O157∶H7的分离鉴定、致病性试验、药物敏感试验以及毒力基因检测。有5份样本经细菌培养特性、生化特性、血清凝集反应和PCR鉴定为大肠杆菌O157∶H7,样本细菌分离率为0.17%。小白鼠致病性试验显示分离菌株的毒力各有差别,对小白鼠的致死率在33.4%～100%之间。药敏结果表明分离菌株对阿莫西林、氨苄西林、多粘菌素B、罗红霉素、利福平和林可霉素不敏感。毒力基因的检测结果表明,5株分离菌株携带的毒力基因略有差异,并与其致病性强弱有一定的相关性。结论大肠杆菌O157∶H7主要在猪群传播,具有一定的毒力,对常用抗生素耐药。

To acquire the epidemiology data of Escherichia coli （E. coli） O157 ： H7 in domestic animals and birds, specimens of animal, feces were collected from the farms in Guangxi province from 2007 to 2010. Five strains of E. coli O157 ： H7 i- solated from 2915 specimens by the methods of morphological, cultural and biochemical characters, serological agglutination re- action as well as PCR identification. The isolated rate was 0.17~. The pathogenicity test showed that isolated E. coli O157 ： H7 had different lethality to mice. The lethality rates of mice were among 33.4% to 100%. Drug susceptibility indicated that isolated E. coli O157 ： H7 were resistance to Amoxycillin, ampicillin, polymyxin B, Roxithromycin, Rifampicin and Lincomycin. Detection of virulence genes of E. coli O157 ： H7 confirmed that the E. coli O157 ： H7 with different virulence genes had some relationship with their lethality to mice. Our investigation indicated that E. coli O157 ： H7 were mainly existed in pig farms, have certain virulence and antibiotic resistance.