Probiotics, prebiotics, and antibiotics in medical management of inflammatory bowel disease

Abstract

The rationale for using probiotics, prebiotics, and antibiotics in IBD is based on convincing evidence that implicates intestinal bacteria in the pathogenesis of the disease. The distal ileum and the colon are the areas with the highest bacterial concentrations and represent the sites of inflammation in IBD. Similarly, pouchitis, the nonspecific inflammation of the ileal reservoir after ileoanal anastomosis, appears to be associated with bacterial overgrowth and dysbiosis. Enteric bacteria and their products have been found within the inflamed mucosa of patients with Crohn's disease (CD) [1]. The composition of the enteric flora is altered in patients with IBD. Increased numbers of aggressive bacteria, such as Bacteroides, adherent/invasive Escherichia coli, and enterococci, and decreased numbers of protective lactobacilli and bifidobacteria have been observed [2]. Manichanh et al. reported a restriction of biodiversity in the fecal microbiota of CD patients [3]. The phylum firmicutes and particularly the species Faecalibacterium prausnitzii are underrepresented in active CD and UC compared with healthy subjects [4], and reduction of F. prausnitzii is associated with higher risk of postoperative recurrence of ileal CD [5]. There is evidence of a loss of immunological tolerance to commensal bacteria in patients with IBD [6]. Patients with CD consistently respond to diversion of fecal stream, with immediate recurrence of inflammation after restoration of intestinal ontinuity or infusion of luminal content into the bypassed ileum [7, 8]. Furthermore, pouchitis does not occur prior to closure of the ileostomy [9].