Genome Comparison and Phylogenetic Analysis of Orientia tsutsugamushi Strains
Genome Comparison and Phylogenetic Analysis of Orientia tsutsugamushi Strains
复制标题
DOI：
10.1093/dnares/dsq018
复制
发表时间：
2010-10-01
期刊：
影响因子：
4.1
通讯作者：
Hayashi, Tetsuya
中科院分区：
文献类型：
--
作者：
Nakayama, Keisuke;Kurokawa, Ken;Hayashi, Tetsuya
恙虫病东方体（OT）是一种专性细胞内细菌，属于立克次体科，是恙虫病或恙虫病的病原体。两个OT菌株（Boryong和Ikeda）的全基因组序列最近已被确定。在本研究中，我们对这些菌株进行了精细的基因组序列比较。我们的研究结果表明，虽然家庭立克次体科的核心基因集是高度保守的两个菌株之间，一组共同的重复序列已爆炸性扩增在两个基因组。这些扩增的重复序列诱导了广泛的基因组改组和许多基因的重复和缺失。在基因组序列比较结果的基础上，我们选择了11个管家基因，并利用这些基因的核苷酸序列对OT菌株进行了多位点序列分析。该分析首次揭示了OT代表菌株的系统发育关系。此外，研究结果表明，存在一个OT谱系具有更高的毒力潜力，这可能解释了在日本的“经典”和“新”类型的恙虫病之间的临床和流行病学差异。
Orientia tsutsugamushi (OT) is an obligate intracellular bacterium belonging to the family Rickettsiaceae and is the causative agent of scrub typhus, or Tsutsugamushi disease. The complete genome sequences of two OT strains (Boryong and Ikeda) have recently been determined. In the present study, we performed a fine genome sequence comparison of these strains. Our results indicate that although the core gene set of the family Rickettsiaceae is highly conserved between the two strains, a common set of repetitive sequences have been explosively amplified in both genomes. These amplified repetitive sequences have induced extensive genome shuffling and duplications and deletions of many genes. On the basis of the results of the genome sequence comparison, we selected 11 house-keeping genes and carried out multilocus sequence analysis of OT strains using the nucleotide sequences of these genes. This analysis revealed for the first time the phylogenetic relationships of representative OT strains. Furthermore, the results suggest the presence of an OT lineage with higher potential for virulence, which may explain the clinical and epidemiological differences between 'classic' and 'new' types of Tsutsugamushi disease in Japan.