温州市食品中肠出血性大肠杆菌O157∶H7污染状况调查

Investigation on the contamination of Enterohemorrhagic escherichia coli O157∶ H7 on food in Wenzhou

目的调查温州市食品中肠出血性大肠杆菌O157∶H7的污染状况,了解肠出血性大肠杆菌O157∶H7毒力因子的携带与耐药情况。方法采用分层随机抽样的方法,对2008—2011年抽取的231份食品样品,用免疫磁珠富集法对大肠杆菌O157∶H7进行分离,对该分离株进行生化、血清学鉴定,以纸片法(K-B法)进行药敏试验;采用PCR方法检测O、H抗原基因和stx1、stx2、eaeA、hlyA等4种毒力基因。结果 231份样品中,分离出1株肠出血性大肠杆菌O157∶H7,检出率为0.43%;O157抗原和H7抗原的核酸检测结果阳性,但未检测到stx1、stx2、eaeA、hlyA等4种毒力基因,菌株对红霉素、利福平、150μg/片和10μg/片两种浓度的0/129(二氨基二异丙基喋啶磷酸盐)耐药。结论温州市食品中存在大肠杆菌O157∶H7的污染,检出率较低,但提示要加强主动监测,通过有效干预,防范肠出血性大肠杆菌O157∶H7所致食源性疾病的发生。

Objective To investigate the contamination of Enterohemorrhagic escherichia coli（EHEC） O157∶ H7 on food in Wenzhou,and to understand its virulent factors and drug resistance.Methods Food samples were collected by random in 2008-2011 and were isolated for EHEC O157∶ H7 by IMS.The contamination of isolates was identified by biochemical methods and serum subtyping and the drug susceptibility was tested by K-B method;O157 and H7 antigen gene and the virulence genes of stx1,stx2,eaeA and hlyA were detected by PCR.Results A EHEC O157∶ H7 strain was isolated from 231 food samples（0.43%）;in which the O157 and H7 antigen gene was positive,but the virulence genes were not detected,and the strain was resistant to erythromycin,rifampin at concentration of 150 μg and 10 μg of 0/129.Conclusion The contamination of EHEC O157∶ H7 was existed in food in Wenzhou,although the detection rate was low.It suggests that strengthening active surveillance through effective intervention to prevent EHEC O157∶ H7 caused by food-borne diseases is necessary.