Distribution of the secondary type III secretion system locus found in enterohemorrhagic Escherichia coli O157:H7 isolates among Shiga toxin-producing E-coli strains
Distribution of the secondary type III secretion system locus found in enterohemorrhagic Escherichia coli O157:H7 isolates among Shiga toxin-producing E-coli strains
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DOI：
10.1128/jcm.41.6.2341-2347.2003
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发表时间：
2003-06-01
影响因子：
9.4
通讯作者：
Sasakawa, C
中科院分区：
文献类型：
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作者：
Makino, SI;Tobe, T;Sasakawa, C
肠出血性大肠杆菌O 157的完整基因组序列的能力，导致一个17-kb的染色体区域，其中包含一个III型分泌系统基因簇在min 64.5的鉴定。该基因座含有开放阅读框，其氨基酸序列与构成III型分泌装置的蛋白质的氨基酸序列显示出高度相似性，所述III型分泌装置由沙门氏菌SPI-1致病岛上的inv-spa-prg基因座编码。将该基因座命名为ETT 2（E.大肠杆菌III型分泌2），由epr、epa和eiv基因组成。ETT 2在肠致病性E.大肠杆菌菌株和一些非O 157滋贺毒素产生菌中也有。大肠杆菌（STEC）菌株，但其中大多数含有ETT 2的截短部分。大多数O 157菌株具有完整的毒素编码基因eae和hlyA以及ETT 2位点，而大多数O26菌株具有毒素编码基因eae和hlyA基因，但ETT 2位点不完整。因此，ETT 2的完整拷贝可能标志着特定STEC菌株的致病性差异。因此，ETT 2基因座的存在可用于鉴定真正致病的STEC菌株，并用于人类和动物中流行菌株的分子指纹分析。
The ability of the complete genome sequence of enterohemorrhagic Escherichia coli O157 led to the identification of a 17-kb chromosomal region which contained a type III secretion system gene cluster at min 64.5. This locus contains open reading frames whose amino acid sequences show high degrees of similarity with those of proteins that make up the type III secretion apparatus, which is encoded by the inv-spa-prg locus on a Salmonella SPI-1 pathogenicity island. This locus was designated ETT2 (E. coli type III secretion 2) and consisted of the epr, epa, and eiv genes. ETT2 was found in enteropathogenic E. coli strains and also in some non-O157 Shiga toxin-producing E. coli (STEC) strains, but most of them contained a truncated portion of ETT2. Most O157 isolates had a complete collection of toxin-encoding genes eae and hlyA and the ETT2 locus, while most O26 strains had toxin-encoding genes eae and hlyA genes but an incomplete ETT2 locus. Thus, an intact copy of ETT2 might mark a pathogenic distinction for particular STEC strains. Therefore, the presence of the ETT2 locus can be used for identification of truly pathogenic STEC strains and for molecular fingerprinting of the epidemic strains in humans and animals.