Detection of toxB, a Plasmid Virulence Gene of Escherichia coli O157, in Enterohemorrhagic and Enteropathogenic E. coli
Detection of toxB, a Plasmid Virulence Gene of Escherichia coli O157, in Enterohemorrhagic and Enteropathogenic E. coli
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肠出血性和肠病性大肠杆菌中大肠杆菌 O157 的质粒毒力基因 toxB 的检测
DOI：
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发表时间：
2005
影响因子：
9.4
通讯作者：
S. Morabito
中科院分区：
文献类型：
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作者：
R. Tozzoli;A. Caprioli;S. Morabito
摘要 大肠杆菌 O157 菌株 EDL933 的毒力质粒携带一个 10 kb 的假定毒力基因，命名为 toxB。关于该基因在大肠杆菌 O157 菌株中的分布或其在其他肠出血性大肠杆菌 (EHEC) 和肠致病性大肠杆菌 (EPEC) 菌株中的存在知之甚少。我们开发了 PCR 和杂交工具来检测整个 toxB 序列，并研究了其在 EHEC O157 菌株和属于不同血清群并从不同来源分离的其他 EHEC 和 EPEC 菌株集合中的存在。 EHEC O157 菌株与所使用的所有 PCR 引物和探针发生反应，从而表明无论分离株是人还是牛来源，都存在完整的 toxB 基因。大约 50% 的测试 EHEC O26 菌株以及其他一些 EHEC 和 EPEC 菌株也观察到类似的阳性反应。然而，与toxB探针杂交的DNA片段的大小与来自EHEC O157的阳性片段的大小不同，表明不同大肠杆菌血清群中存在的toxB基因存在多态性。此外，属于不同血清群的几种EHEC和EPEC菌株仅与所使用的一些遗传工具发生反应，这表明toxB主要变体的存在或该基因片段的存在。 Southern 印迹分析表明，toxB 序列也位于 EHEC 和 EPEC O26 中的大质粒上。
ABSTRACT The virulence plasmid of Escherichia coli O157 strain EDL933 carries a 10-kb putative virulence gene designated toxB. Little is known about the distribution of this gene among E. coli O157 strains or its presence in other enterohemorrhagic E. coli (EHEC) and enteropathogenic E. coli (EPEC) strains. We developed PCR and hybridization tools for the detection of the entire toxB sequence and investigated its presence in a collection of EHEC O157 strains and other EHEC and EPEC strains belonging to different serogroups and isolated from different sources. The EHEC O157 strains reacted with all of the PCR primers and probes used, thus indicating the presence of a complete toxB gene regardless of the human or bovine origin of the isolates. Similar positive reactions were observed for about 50% of the EHEC O26 strains tested and a few other EHEC and EPEC strains. However, the size of the DNA fragments hybridizing with the toxB probes differed from that of the positive fragments from EHEC O157, suggesting a polymorphism in the toxB genes present in the different E. coli serogroups. Moreover, several EHEC and EPEC strains belonging to different serogroups reacted with only some of the genetic tools used, suggesting either the existence of major variants of toxB or the presence of fragments of the gene. Southern blotting analysis showed that toxB sequences were located on large plasmids in EHEC and EPEC O26 as well.
影响因子：
56.9
作者：
OBRIEN, AD;NEWLAND, JW;FORMAL, SB
通讯作者：
FORMAL, SB