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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 O157: H7 in foodstuffs of Wenzhou City and to understand the carriage and drug resistance of enterohemorrhagic Escherichia coli O157: H7 virulence factors. Methods Stratified random sampling method was used to separate 231 strains of food samples collected from 2008 to 2011 by immunomagnetic beads enrichment method for E. coli O157: H7. The biochemical and serological identification of this isolate was carried out. (KB method) for susceptibility testing; PCR method was used to detect O and H antigen genes and four virulence genes stx1, stx2, eaeA and hlyA. Results One strain of enterohemorrhagic Escherichia coli O157: H7 was isolated from 231 samples and the detection rate was 0.43%. The results of nucleic acid detection of O157 antigen and H7 antigen were positive, but stx1, stx2, eaeA and hlyA were not detected The virulence genes, strains were resistant to erythromycin, rifampin, 150 μg / tablet and 10 μg / tablet of 0/129 (diaminodipropylphosphonates). Conclusion The contamination of Escherichia coli O157: H7 in the food of Wenzhou City is low and the detection rate is low. However, it is suggested that active surveillance should be strengthened to prevent foodborne diseases caused by enterohemorrhagic Escherichia coli O157: H7 through effective intervention.