J Clin Gastroenterol. 2007 May/June;41 Suppl 1:S33-S36.
Role of Gut Bacteria in Patients With Irritable Bowel Syndrome.
Noureddin M, Lin HC. Division of Gastrointestinal and Liver Diseases, Keck School of Medicine, University of Southern California, Los Angeles, CA daggerGastroenterology Section, New Mexico VA Health Care System, University of New Mexico, Albuquerque, NM.
Irritable bowel syndrome (IBS) is a common diagnosis in gastroenterology with patients usually subgrouped under the Rome clinical criteria according to their bowel pattern. Although an individual may be classified as diarrhea-predominant IBS or constipation-predominant IBS, patients often resist this subgrouping by saying that they have both constipation and diarrhea. Regardless of their predominant bowel complaint, 92% of IBS patients share the symptom of bloating. Bloating secondary to abnormal bacterial fermentation is a feature of small intestinal bacterial overgrowth (SIBO). The role for an antibiotic-sensitive mechanism in IBS such as SIBO is supported by 2 double-blind, randomized, placebo-controlled trial showing: (1) a 75% improvement in global bowel symptoms when bacterial overgrowth was successfully treated with a nonabsorbable antibiotic and (2) a sustained improvement of symptoms for a period of 10 weeks after the treatment with a small bowel-targeting antibiotic. Although diarrhea is a well-known symptom in SIBO, constipation may also be a consequence of altered host-gut microbial relationship through the action of the bacterial gas methane on intestinal motility. In addition to bloating and bowel symptoms, a number of extraintestinal complaints are common in patients with IBS, including psychologic changes such as anxiety. Animal data would suggest that anxiety may also be a consequence of altered host-gut microbial relationship. In this review, we will discuss the role of gut bacteria in the gastrointestinal and extraintestinal presentations of IBS.
PMID: 17438416 [PubMed - as supplied by publisher]