Influences of intestinal bacteria in human inflammatory bowel disease.

Microbes that reside in the human intestinal tract and interact with immune and epithelial cells are strongly implicated as causative or predisposing agents of inflammatory bowel disease (IBD). Recent studies using metagenomic approaches have revealed differences in the fecal and mucosa-associated microbiota of patients with IBD, but it remains unclear whether this is a cause or consequence of chronic intestinal inflammation. A few microbes have been singled out as candidate pathogens in IBD and remain the subject of ongoing study. Complex imbalances in gut bacterial community structure and/or deficiencies in their functional capabilities may be a greater issue in IBD development. A more complete understanding of host-microbiota interactions in IBD is hampered by several remaining but surmountable methodological and technical challenges.