Bacteria in the pathogenesis of inflammatory bowel disease.
OBJECTIVE
Inflammatory bowel disease is thought to result from an abnormal response to the gut microbiota. This review discusses advances in knowledge of the changes in gut microbiota and host response in inflammatory bowel disease.


RESULTS
Approximately 15% of Crohn's disease cases in western populations result from mutations in NOD2/CARD15. This disease leads to defective intestinal defensin production and defective monocyte interleukin-8 response to bacterial peptidoglycan. A similar defective interleukin-8 response and consequent delayed neutrophil recruitment have also been shown in patients with Crohn's disease who do not have the NOD2 mutation. A consequence seems to be the accumulation in tissue of macrophages containing various bacteria, perhaps particularly Escherichia coli. In keeping with this patients with Crohn's disease have circulating antibodies against bacterial flagellar proteins of enterobacteria and clostridia. In ulcerative colitis, there is less evidence for invasion by or immune response to bacteria but changes in gut microbiota include a relative deficiency of bifidobacteria. There is considerable interest in probiotic or prebiotic therapies although so far little evidence for their efficacy.


CONCLUSIONS
Molecular techniques are giving us better insight into the gut microbiota in inflammatory bowel disease that should translate into improved therapies.
Subramanian
Sreedhar
S
Division of Gastroenterology, School of Clinical Sciences, University of Liverpool, Liverpool, UK.
Campbell
Barry James
BJ
Rhodes
Jonathan Michael
JM
D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D015551:Autoimmunity; D001419:Bacteria / Q000302:isolation & purification*; D004195:Disease Models, Animal; D004926:Escherichia coli / Q000302:isolation & purification; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000188:drug therapy* / Q000276:immunology / Q000382:microbiology*; D007422:Intestines / Q000382:microbiology*; D051379:Mice; D019936:Probiotics / Q000627:therapeutic use*
D000900:Anti-Bacterial Agents