Department of Medical Microbiology, University Medical Centre Utrecht, Utrecht, The Netherlands.
PLoS One. 2010 Jan 13;5(1):e8662. doi: 10.1371/journal.pone.0008662.
Horizontal gene transfer is a key step in the evolution of Enterobacteriaceae. By acquiring virulence determinants of foreign origin, commensals can evolve into pathogens. In Enterobacteriaceae, horizontal transfer of these virulence determinants is largely dependent on transfer by plasmids, phages, genomic islands (GIs) and genomic modules (GMs). The High Pathogenicity Island (HPI) is a GI encoding virulence genes that can be transferred between different Enterobacteriaceae. We investigated the HPI because it was present in an Enterobacter hormaechei outbreak strain (EHOS). Genome sequence analysis showed that the EHOS contained an integration site for mobile elements and harbored two GIs and three putative GMs, including a new variant of the HPI (HPI-ICEEh1). We demonstrate, for the first time, that combinatorial transfers of GIs and GMs between Enterobacter cloacae complex isolates must have occurred. Furthermore, the excision and circularization of several combinations of the GIs and GMs was demonstrated. Because of its flexibility, the multiple integration site of mobile DNA can be considered an integration hotspot (IHS) that increases the genomic plasticity of the bacterium. Multiple combinatorial transfers of diverse combinations of the HPI and other genomic elements among Enterobacteriaceae may accelerate the generation of new pathogenic strains.
水平基因转移是肠杆菌科进化的关键步骤。通过获得外来来源的毒力决定因素，共生菌可以进化为病原体。在肠杆菌科中，这些毒力决定因素的水平转移在很大程度上依赖于质粒、噬菌体、基因组岛 (GI) 和基因组模块 (GM) 的转移。高致病性岛 (HPI) 是一个 GI，编码可以在不同肠杆菌科之间转移的毒力基因。我们研究了 HPI，因为它存在于肠杆菌属 Hormaechei 爆发株 (EHOS) 中。基因组序列分析表明，EHOS 含有一个移动元件的整合位点，并且包含两个 GI 和三个推定的 GM，包括 HPI 的一个新变体 (HPI-ICEEh1)。我们首次证明，肠杆菌属 cloacae 复合菌株之间必须发生 GI 和 GM 的组合转移。此外，还证明了 GI 和 GM 的几种组合的切除和环化。由于其灵活性，移动 DNA 的多个整合位点可被视为整合热点 (IHS)，增加了细菌的基因组可塑性。肠杆菌科中 HPI 和其他基因组元件的多种组合的多次组合转移可能会加速新致病菌株的产生。
