School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, Australia.
Infect Immun. 2012 Feb;80(2):883-90. doi: 10.1128/IAI.06031-11. Epub 2011 Nov 28.
The recent detection and isolation of the aflagellate Campylobacter ureolyticus (previously known as Bacteroides ureolyticus) from intestinal biopsy specimens and fecal samples of children with newly diagnosed Crohn's disease led us to investigate the pathogenic potential of this bacterium. Adherence and gentamicin protection assays were employed to quantify the levels of adherence to and invasion into host cells. C. ureolyticus UNSWCD was able to adhere to the Caco-2 intestinal epithelial cell line with a value of 5.341% ± 0.74% but was not able to invade the Caco-2 cells. The addition of two proinflammatory cytokines, tumor necrosis factor alpha (TNF-α) and gamma interferon (IFN-γ), to the cell line did not affect attachment or invasion, with attachment levels being 4.156% ± 0.61% (P = 0.270) for TNF-α and 6.472% ± 0.61% (P = 0.235) for IFN-γ. Scanning electron microscopy visually confirmed attachment and revealed that C. ureolyticus UNSWCD colonizes and adheres to intestinal cells, inducing cellular damage and microvillus degradation. Purification and identification of the C. ureolyticus UNSWCD secretome detected a total of 111 proteins, from which 29 were bioinformatically predicted to be secretory proteins. Functional classification revealed three putative virulence and colonization factors: the surface antigen CjaA, an outer membrane fibronectin binding protein, and an S-layer RTX toxin. These results suggest that C. ureolyticus has the potential to be a pathogen of the gastrointestinal tract.
最近从新诊断为克罗恩病的儿童的肠道活检标本和粪便样本中检测到并分离出无鞭毛的解脲弯曲杆菌（以前称为解脲拟杆菌），这促使我们研究该细菌的致病潜力。我们采用黏附和庆大霉素保护试验来定量测定其黏附到和侵入宿主细胞的水平。解脲弯曲杆菌 UNSWCD 能够以 5.341%±0.74%的水平黏附到 Caco-2 肠上皮细胞系，但不能侵入 Caco-2 细胞。将两种促炎细胞因子，肿瘤坏死因子-α（TNF-α）和γ干扰素（IFN-γ）添加到细胞系中，不会影响黏附或侵入，TNF-α的黏附水平为 4.156%±0.61%（P=0.270），IFN-γ的黏附水平为 6.472%±0.61%（P=0.235）。扫描电子显微镜直观地证实了黏附作用，并显示解脲弯曲杆菌 UNSWCD 定植并黏附到肠细胞上，诱导细胞损伤和微绒毛降解。解脲弯曲杆菌 UNSWCD 分泌组的纯化和鉴定共检测到 111 种蛋白质，其中 29 种经生物信息学预测为分泌蛋白。功能分类揭示了三个可能的毒力和定植因子：表面抗原 CjaA、一种外膜纤维连接蛋白结合蛋白和一种 S-层 RTX 毒素。这些结果表明解脲弯曲杆菌具有成为胃肠道病原体的潜力。
