chapter  4
Microbiota and psychological processes and IBD
Pages 10

Infl ammatory bowel diseases (IBD) are thought to develop as a result of an exaggerated immune response to the gut microbiota. Animal models of infl ammation require bacteria to produce infl ammation (Sartor 2004). Antibiotics are effective in Crohn’s disease (CD), pouchitis and ulcerative colitis (UC), and probiotics have therapeutic effi cacy in pouchitis and UC (Sartor 2004). Diversion of the faecal stream from the infl amed gut induces healing in CD, while re-infusion of intestinal content into surgically excluded ileum triggers early disease recurrence (D’Haens et al. 1998). These fi ndings have helped establish that the gut microbiota is a key contributor to IBD pathogenesis, with disease more prevalent in genetically susceptible individuals (Jostins et al. 2012).