Campylobacter concisus and inflammatory bowel disease.

Investigation of the possible role of Campylobacter concisus (C. concisus) in inflammatory bowel disease (IBD) is an emerging research area. Despite the association found between C. concisus and IBD, it has been difficult to explain how C. concisus, a bacterium that is commonly present in the human oral cavity, may contribute to the development of enteric diseases. The evidence presented in this review shows that some C. concisus strains in the oral cavity acquired zonula occludens toxin (zot) gene from a virus (prophage) and that C. concisus Zot shares conserved motifs with both Vibrio cholerae Zot receptor binding domain and human zonulin receptor binding domain. Both Vibrio cholerae Zot and human zonulin are known to increase intestinal permeability by affecting the tight junctions. Increased intestinal permeability is a feature of IBD. Based on these data, we propose that a primary barrier function defect caused by C. concisus Zot is a mechanism by which zot-positive C. concisus strains may trigger the onset and relapse of IBD.