2007年浙江省衢州地区动物中产志贺毒素大肠埃希菌O157:H7感染状况

目的:了解2007年浙江省衢州地区产志贺毒素大肠埃希菌O157:H7在动物中的分布情况及其耐药性、PFGE分型及毒力基因携带状况。方法:按全国O157:H7监测方案于5~10月份肠道传染病高发季节,在衢州地区采集各种动物粪便/肛拭,用免疫磁珠富集后进行O157:H7分离培养、鉴定,可疑菌株以PCR法检测O、H抗原及志贺样毒素(SLT1和SLT2)、粘附抹平因子(eaeA)及溶血素(hly)4种毒力基因。用脉冲场凝胶电泳(pulse field gel electrophoresis,PFGE)方法进行同源性分析,同时选择14种抗生素进行药敏试验,分析分离所得菌株的耐药状况。结果:共监测动物粪便标本300份,分离得产志贺毒素大肠埃希菌O157:H7菌株16株,分离率为5.33%。16株O157:H7菌株,毒力基因Hly、eaeA、SLT2均阳性,SLT1均阴性。脉冲场凝胶电泳分型显示,16株O157:H7菌株可分2个PFGE基因型,型间差异较小。耐药性分析显示这些菌株对红霉素、利福平的耐药率最高,达100.0%,对其他受试抗生素均敏感。结论:该地区动物中产志贺毒素大肠埃希菌O157:H7带菌率较高,所分离菌株主要携带SLT2基因,因此推测该地区存在发生产志贺毒素大肠埃希菌O157:H7感染暴发或流行的潜在危险,需增加对动物源性O157:H7的监测力度。

Preliminary study of Escherichia coli O157:H7 infectious status among animals in Quzhou Prefecture of Zhejiang Province

Objective:To investigate the prevalence of Escherichia coli O157:H7 in reservoirs in Quzhou prefecture of Zhejiang Province and study drug resistance,virulence genes and pulse field gel electrophoresis(PFGE) patterns of them.Methods:According to the strategies on National Surveillance of E.coli O157:H7,we collected stool samples of animals in Quzhou Prefecture of Zhejiang Province from May to October while enteric infectious diseases were highly prevalent E.coli O157:H7 strains were isolated and cultured by immunomagnetic separation(IMS).The virulence genes,including SLT1,SLT2,hly and eae,were examined by routine PCR.Homology analysis was performed with PFGE and antimicrobial susceptibility tests were performed with 14 antibiotics.Results:The 16 strains E.coli O157:H7(5.33%) were isolated from 300 faecal samples.PCR results shows that SLT2,hly and eaeA were all positive and SLT1 was negative in 16 E.coli O157:H7 strains.There were 2 PFGE patterns in these E.coli O157:H7 isolates.Little difference were found between these two patterns.Analysis shows these isolates are totally resistant to erythromycin(100%) and rifampicin(100%) and they are susceptible to the other tested antibiotics.Conclusion:The prevalence rate of Escherichia coli O157:H7 carrying virulence genes especially SLT2 is found high in reservoirs in Quzhou Prefecture of Zhejiang Province.There exists potential danger of the outbreak and prevalence of Escherichia coli O157:H7 in this area.It suggests that the epidemiological investigation and checking work for O157:H7 should be reinforced.