School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW 2052, Australia.
Gut Pathog. 2011 Oct 13;3:15. doi: 10.1186/1757-4749-3-15.
Several studies have shown that significant genotypic heterogeneity exists among Campylobacter concisus strains. Recently, the genome of C. concisus UNSWCD, isolated from a patient with Crohn's disease, was sequenced.
In this study, comparative analyses were performed between strain UNSWCD and BAA-1457, isolated from a patient with acute gastroenteritis. Searches between C. concisus UNSWCD and BAA-1457 showed that 76% of genes were homologues, whereas those between C. jejuni strains showed 90-91% to be homologues, indicating substantial variation exists within these two C. concisus genomes. More specific bidirectional homology searches identified 1593 genes that are shared between these strains, and 115 and 281 genes unique to UNSWCD and BAA-1457, respectively. Significantly, differences in the type of flagellin glycosylation pathways between the two strains were identified and confirmed by PCR. The protein profiles of UNSWCD, BAA-1457 and a further six strains of C. concisus were compared and analyzed bioinformatically, and this differentiated the strains into four clades. BAA-1457 was found to be highly divergent (average similarity: 56.8%) from the other seven strains (mean average similarity ± standard deviation: 64.7 ± 1.7%). Furthermore, searches for homologues of the 1593 proteins found to be common between UNSWCD and BAA-1457 were conducted against all available bacterial genomes, and 18 proteins were found to be unique to C. concisus, of which 6 were predicted to be secreted, and may represent good markers for detection of this species.
This study has elucidated several features that may be responsible for the heterogeneity that exists among C. concisus strains, and has determined that the strain BAA-1457 is genetically atypical to other C. concisus strains and is not a good candidate reference strain.
多项研究表明，弯曲菌属中的空肠弯曲菌存在显著的基因型异质性。最近，分离自克罗恩病患者的空肠弯曲菌 UNSWCD 的基因组被测序。
在本研究中，对 UNSWCD 菌株和从急性胃肠炎患者中分离的 BAA-1457 菌株进行了比较分析。UNSWCD 与 BAA-1457 之间的搜索表明，76%的基因是同源的，而空肠弯曲菌菌株之间的搜索表明 90-91%是同源的，这表明这两个空肠弯曲菌基因组之间存在很大的差异。更具体的双向同源性搜索确定了这两个菌株之间共享的 1593 个基因，以及分别为 UNSWCD 和 BAA-1457 所特有的 115 个和 281 个基因。值得注意的是，在两种菌株之间的鞭毛糖基化途径的类型上存在差异，并通过 PCR 进行了确认。对 UNSWCD、BAA-1457 和另外六个空肠弯曲菌菌株的蛋白图谱进行了比较和生物信息学分析，将这些菌株分为四个分支。BAA-1457 与其他七个菌株（平均相似性：56.8%）高度分化（平均相似性±标准差：64.7±1.7%）。此外，对在 UNSWCD 和 BAA-1457 之间发现的 1593 个共同蛋白的同源物进行了搜索，这些同源物针对所有可用的细菌基因组进行了搜索，发现了 18 个独特于空肠弯曲菌的蛋白，其中 6 个被预测为分泌蛋白，可能是空肠弯曲菌检测的良好标志物。
本研究阐明了可能导致空肠弯曲菌菌株之间存在异质性的一些特征，并确定了 BAA-1457 菌株在遗传上与其他空肠弯曲菌菌株不同，不是一个好的候选参考菌株。
