Molecular and phenotypic profiling of sorbitol-fermenting Escherichia coli O157:H- human isolates from Finland
Molecular and phenotypic profiling of sorbitol-fermenting Escherichia coli O157:H- human isolates from Finland
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DOI：
10.1111/j.1469-0691.2006.01478.x
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发表时间：
2006-07-01
影响因子：
14.2
通讯作者：
Siitonen, A.
中科院分区：
文献类型：
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作者：
Eklund, M.;Bielaszewska, M.;Siitonen, A.
本研究对9株产β-葡萄糖醛酸酶（beta-glucuronidase，SF）的大肠杆菌中的stx 1、stx 2、stx 2c、stx 2d、stx 2 e、eae及其亚型（α、β、γ、β）、efa 1、cdt-V簇、肠出血性大肠杆菌（EHEC）-hlyA、katP、espP、etpD、sfpA和鞭毛fliC基因等毒力相关基因进行了研究。1997年至2001年期间从芬兰人中获得的大肠杆菌O 157：H-（非运动型）分离株。此外，还研究了滋贺毒素（Stx）、细胞致死性膨胀毒素（CDT）-V和肠出血性大肠杆菌溶血素（EHEC-Hly）的产生情况，并进行了噬菌体型（PT）和脉冲场凝胶电泳（PFGE）分型。所有9个分离株携带eae-γ，efa 1，EHEC-hlyA，etpD，sfpA和fliC; 8个还携带cdt-V基因簇，5个对stx 2呈阳性。所有分离株均不含stx 1、stx 2c、stx 2d、stx 2 e、katP和espP。所有携带相应基因的分离株也产生Stx 2和CDT-V，滴度范围分别为1：32至1：128和1：2至1：4。所有分离株在肠溶血素琼脂上均不表达EHEC-Hly。7株属于PT 88，2株具有PT 88变异型。7个分离物表现出密切的遗传关系，PFGE相似性指数（SI）为92- 98%。两个分离株，时间上的第一个和最后一个，间隔5年，是最分歧的（SI分别为71%和85%）。研究表明，SF E.芬兰分离的O 157：H-大肠杆菌与SF E有密切的亲缘关系。大肠杆菌O 157菌株分离自德国。这一发现表明SF E具有克隆性。大肠杆菌O 157：H-菌株。
This study investigated the occurrence of virulence-associated genes, including stx1, stx2, stx2c, stx2d, stx2e, eae and its subtypes (alpha, beta, gamma, epsilon), efa1, cdt-V cluster, enterohaemorrhagic Escherichia coli (EHEC)-hlyA, katP, espP, etpD, sfpA and the flagellar fliC gene, in nine sorbitol-fermenting (SF), beta-glucuronidase-positive E. coli O157:H- (non-motile) isolates obtained from humans in Finland between 1997 and 2001. In addition, the production of Shiga toxin (Stx), cytolethal distending toxin (CDT)-V and EHEC haemolysin (EHEC-Hly) was studied, and the phage type (PT) and pulsed-field gel electrophoresis (PFGE) types were determined. All nine isolates carried eae-gamma, efa1, EHEC-hlyA, etpD, sfpA and fliC; eight also harboured the cdt-V gene cluster and five were positive for stx2. None of the isolates harboured stx1, stx2c, stx2d, stx2e, katP or espP. All isolates harbouring the corresponding genes also produced Stx2 and CDT-V in titres ranging from 1:32 to 1:128 and from 1:2 to 1:4, respectively. None of the isolates expressed EHEC-Hly on enterohaemolysin agar. Seven isolates belonged to PT88 and two had a PT88 variant pattern. Seven isolates showed a close genetic relationship, with a PFGE similarity index (SI) of 92-98%. Two isolates, temporally the first and last, obtained 5 years apart, were the most divergent (SI of 71% and 85%, respectively). The study demonstrated that SF E. coli O157:H- isolates from Finland are closely related and show a close relationship with SF E. coli O157 strains isolated in Germany. This finding suggests a clonality of SF E. coli O157:H- isolates from different geographical regions.