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目的了解2012-2015年河南省出血性大肠埃希菌EHEC:O157病原学与PFGE脉冲场凝胶电泳指纹图谱特征,为相应食源性疾病的监测、预测预警、暴发溯源调查提供基线数据。方法对河南省2012-2015年采自腹泻病人及动物粪便和食品标本进行mEC肉汤增菌,经免疫磁珠富集后采用ChromagarO157平板分离培养;采用系统生化鉴定大肠埃希菌,并进行EHEC:O157单抗血清玻片凝集试验;采用多重PCR鉴定出血性大肠埃希菌O157及携带的毒力基因。根据“PulseNet China”公布的EHEC O157PFGE分型技术标准,对阳性菌株进行PFGE指纹图谱分析。结果47株出血性大肠埃希菌O157中1株产志贺毒素1(STX1),2株产志贺毒素2(STX2);21株携带粘附素(eaeA)和溶血素(hlyA)毒力基因,其余23株为不产毒型;经XbaI酶切后进行脉冲场凝胶电泳,共分为40种不同带型,相似度区间为64.20%-100%,各带型包含菌株数为1~2株不等,人源与食品动物源菌株带型未发现聚集关联性。结论河南省检出的EHEC:O157中既有携带不同毒力基因的菌株,也有非产毒型菌株,其PFGE指纹图谱呈现高度分散性与多态性,体现了食源性细菌病原体所具有的多样性与复杂性。
Objective To understand the characteristics of EHEC: O157 etiology and PFGE pulsed-field gel electrophoresis fingerprinting of Hemorrhagic Escherichia coli from 2012 to 2015 in Henan Province, and to provide baseline data for monitoring, predicting and warning of outbreaks of foodborne diseases and origin tracing investigation. Methods Enrichment of bacteria in mEC broth collected from diarrhea patients and animal feces and food samples from 2012 to 2015 in Henan province was carried out. The immunomagnetic beads were enriched and separated by ChromagarO157 plate. The biochemical identification of Escherichia coli was carried out and EHEC : O157 monoclonal antibody serum slide agglutination test; multiplex PCR was used to identify hemorrhagic Escherichia coli O157 and carry virulence genes. According to the standard “EHEC O157PFGE” published by “PulseNet China”, PFGE fingerprinting of positive strains was carried out. Results 1 strain of STX1 and 2 strains of STX2 were isolated from 47 strains of E.coli O157. Twenty-one isolates contained virulence of eaeA and hlyA The other 23 strains were non-toxin-producing. After digested by XbaI, they were divided into 40 different bands with the similarity interval of 64.20% -100%, and the number of strains in each band was 1 ~ 2 strains, human and food animal strains strains found no aggregation. Conclusion The strains of EHEC: O157 detected in Henan province contain not only virulent strains but also virulent strains. The PFGE fingerprints of the strains are highly dispersible and polymorphic, indicating that the bacterial pathogens of foodborne pathogens Diversity and complexity.