Skarp C P A, Akinrinade O, Kaden R, Johansson C, Rautelin H
Department of Medical Sciences, Clinical Microbiology, Uppsala University, Uppsala, Sweden.
Children's Hospital Helsinki, Pediatric Cardiology, University of Helsinki and Helsinki University Central Hospital, Finland.
Int J Med Microbiol. 2017 Jun;307(4-5):233-240. doi: 10.1016/j.ijmm.2017.04.001. Epub 2017 Apr 3.
Campylobacter jejuni is an important foodborne pathogen and the most commonly reported bacterial cause of gastroenteritis. C. jejuni is occasionally found in blood, although mechanisms important for invasiveness have remained unclear. C. jejuni is divided into many different lineages, of which the ST21 clonal complex (CC) is widely distributed. Here, we performed comparative genomic and in vitro analyses on 17C. jejuni ST21CC strains derived from human blood and feces in order to identify features associated with isolation site. The ST21CC lineage is divided into two large groups; centered around ST-21 and ST-50. Our clinical strains, typed as ST-50, showed further microevolution into two distinct clusters. These clusters were distinguished by major differences in their capsule loci and the distribution of accessory genetic content, including C. jejuni integrated elements (CJIEs) and plasmids. Accessory genetic content was more common among fecal than blood strains, whereas blood strains contained a hybrid capsule locus which partially consisted of C. jejuni subsp. doylei-like content. In vitro infection assays with human colon cell lines did not show significant differences in adherence and invasion between the blood and fecal strains. Our results showed that CJIEs and plasmid derived genetic material were less common among blood isolates than fecal isolates; in contrast, hybrid capsule loci, especially those containing C. jejuni subsp. doylei-like gene content, were found among many isolates derived from blood. The role of these findings requires more detailed investigation.
空肠弯曲菌是一种重要的食源性病原体，也是最常报告的细菌性肠胃炎病因。空肠弯曲菌偶尔会在血液中发现，但其侵袭性的重要机制仍不清楚。空肠弯曲菌可分为许多不同的谱系，其中ST21克隆复合体（CC）分布广泛。在此，我们对17株源自人类血液和粪便的空肠弯曲菌ST21CC菌株进行了比较基因组学和体外分析，以确定与分离部位相关的特征。ST21CC谱系分为两大组，以ST-21和ST-50为中心。我们鉴定为ST-50型的临床菌株进一步微进化为两个不同的簇。这些簇的区别在于其荚膜位点以及包括空肠弯曲菌整合元件（CJIEs）和质粒在内的辅助遗传内容的分布存在重大差异。辅助遗传内容在粪便菌株中比血液菌株中更常见，而血液菌株含有一个混合荚膜位点，该位点部分由空肠弯曲菌亚种多伊氏菌样内容组成。用人结肠细胞系进行的体外感染试验未显示血液菌株和粪便菌株在黏附和侵袭方面有显著差异。我们的结果表明，CJIEs和质粒衍生的遗传物质在血液分离株中比粪便分离株中更少见；相反，在许多源自血液的分离株中发现了混合荚膜位点，尤其是那些含有空肠弯曲菌亚种多伊氏菌样基因内容的位点。这些发现的作用需要更详细的研究。
