Octamer-based genome scanning distinguishes a unique subpopulation of Escherichia coli O157:H7 strains in cattle
Octamer-based genome scanning distinguishes a unique subpopulation of Escherichia coli O157:H7 strains in cattle
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DOI：
10.1073/pnas.96.23.13288
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发表时间：
1999-11-09
影响因子：
11.1
通讯作者：
Benson, AK
中科院分区：
文献类型：
--
作者：
Kim, J;Nietfeldt, J;Benson, AK
多位点基因分型方法表明，大肠杆菌O157：H7是一个地理分布的克隆。然而，高分辨率的方法，如脉冲场凝胶电泳显示显着的基因组多样性之间的不同菌株。目的探讨人源和牛源大肠杆菌分离株的亲缘关系。大肠杆菌O157：H7的详细，我们已经开发了一个八聚体为基础的基因组扫描方法，比较之间的距离过度代表，链偏置八聚体发生在基因组中。来自基因组的st megabacterium的基于八聚体的基因组扫描产物的比较证明了在美国传播的两种不同的大肠杆菌O157：H7谱系的存在。人类和牛的分离株是非随机分布的谱系，这表明这些谱系之一可能是人类的毒性较低，或可能不会有效地从牛源传播给人类。利用人字形噬菌体基因组进行的限制性片段长度多态性分析表明，噬菌体介导的事件与谱系的分歧有关，从而为通过其他分子指纹分析方法在大肠杆菌O157：H7中观察到的多样性程度提供了一种解释。
Multilocus-genotyping methods have shown that Escherichia coli O157:H7 is a geographically disseminated clone. However, high-resolution methods such as pulse-field gel electrophoresis demonstrate significant genomic diversity among different isolates. To assess the genetic relationship of human and bovine isolates of E. coli O157:H7 in detail, we have developed an octamer-based genome-scanning methodology, which compares the distance between over-represented, strand-biased octamers that occur in the genome. Comparison of octamer-based genome-scanning products derived from st megabase of the genome demonstrated the existence of two distinct lineages of E, coli O157:H7 that are disseminated within the United States. Human and bovine isolates are nonrandomly distributed among the lineages, suggesting that one of these lineages may be less virulent for humans or may not be efficiently transmitted to humans from bovine sources. Restriction fragment length polymorphism analysis with lambdoid phage genomes indicates that phage-mediated events are associated with divergence of the lineages, thereby providing one explanation for the degree of diversity that is observed among E, coli O157:H7 by other molecular-fingerprinting methods.