文章摘要
罗霞,叶长芸,李芳,汪华,任军,景怀琦,徐建国.大肠埃希菌O157∶H7携带stx2::IS1203v基因研究[J].中华流行病学杂志,2007,28(11):1119-1122
大肠埃希菌O157∶H7携带stx2::IS1203v基因研究
Identification of harboring stx2::ISl203 Escherichia coli“O157:H7 strains isolated in China
投稿时间:2007-05-31  
DOI:
中文关键词: 大肠埃希菌0157:H7;志贺毒素;插入序列1203v
英文关键词: Escherichia coli 0157: H7;Shiga toxin; Insertion sequence 1203v
基金项目:
作者单位
罗霞 中国疾病预防控制中心传染病预防控制所传染病预防控制国家重点实验室, 北京, 102206 
叶长芸 中国疾病预防控制中心传染病预防控制所传染病预防控制国家重点实验室, 北京, 102206 
李芳 大连医科大学基础医学院 
汪华 江苏省疾病预防控制中心 
任军 安徽省疾病预防控制中心) 
景怀琦 中国疾病预防控制中心传染病预防控制所传染病预防控制国家重点实验室, 北京, 102206 
徐建国 中国疾病预防控制中心传染病预防控制所传染病预防控制国家重点实验室, 北京, 102206 
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中文摘要:
      目的了解中国部分地区大肠埃希菌0157:H7菌株携带志贺毒素基因变异状况。方法采用聚合酶链反应扩增志贺毒素基因,使用核苷酸序列测定判断是否存在志贺毒素的新变种,用HeLa细胞毒性实验研究其细胞毒性的变化。结果1992-2002年中国部分地区分离到的289株产志贺毒素的大肠埃希菌0157:H7中有3株菌携带的志贺毒素2(stx2)基因有1.3 kb的插入序列(IS)插入,且这段IS和ISl203变种(ISl203 variant,ISl203v)有100%的核苷酸序列同源性。ISl203v插入到3株大肠埃希菌0157:H7 stx2基因的位置及开放性读码框(ORF)方向有所不同。除此之外,3株菌原有的stx2基因序列完全一致且为stx2原型毒素。和Stx2原型毒素相比,这3株携带stx2::ISl203v基因的菌株对HeLa细胞的毒性明显降低。结论分离到ISl203v插入stx2基因的大肠埃希菌0157:H7菌株;ISl203v的插入可导致对HeLa细胞的细胞毒性降低。
英文摘要:
      objective To understand the variation of shiga toxin(stx)genes of Escheria coliO157:H7 strains isolated in China.methods P01ymerase chain reaction(PCR)was used to identity thetypes of stx genes and the nucleotide sequences of the amplified stx variants genes were determined.Compare to the cytotoxicity of StX,variants were tested by HeLa ceU assay.Reults We found novel stx2genes in 3 of 289 strains of Shiga toxin-producing E.coZi 0157:H7 iS0lated from 1999 to 2002 in China.The novel stx2 genes were inserted by a 1.3.kb insertion sequence(IS)and the nucleotide sequences of ISshowed 100%homology with that of ISl203 variant(ISl203v).The ISl203v inserted in the stx2 genes ofthree E.cozi 0157:H7 strains at different sites and the direction of the open reading frames(0RFs)ofISl203v of each strain was different.In addition to the above mentioned findings,the nucleotide sequencesof three stx2 genes were mpIetely identical and the type of the three Stx2 was Stx2 prototype.Cbmpare tothe cytotoxicity of Stx2 prototype,the novel Stx2 was found to be obviously 10wer.conclusion E.coli0157:H7 strains harboring stx2::ISl203v genes were iSolated in China.Consequently,the results of HeLacell assay showed that the insertion of ISl203v coukl lead to low cytotoxicity of Stx2.
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