Small intestinal bacterial overgrowth in patients with irritable bowel syndrome

• Published in: Gut Vol. 56; no. 6; pp. 802 - 808
• Main Authors: Posserud, Iris, Stotzer, Per-Ove, Björnsson, Einar S, Abrahamsson, Hasse, Simrén, Magnus
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd and British Society of Gastroenterology 01.06.2007; BMJ; BMJ Publishing Group LTD; BMJ Group
• Subjects: Adult; Aged; Anti-Bacterial Agents; Anti-Bacterial Agents - therapeutic use; Antibiotics; Bacteria; Bacteria - growth & development; Bacteria - isolation & purification; Bacterial Infections; Bacterial Infections - complications; Bacterial Infections - drug therapy; Biological and medical sciences; Breath Tests; Breath Tests - methods; complications; Constipation; Constipation - microbiology; Constipation - physiopathology; Diarrhea; Diarrhea - microbiology; Diarrhea - physiopathology; drug therapy; Female; Gastroenterologi och hepatologi; Gastroenterology and Hepatology; Gastroenterology. Liver. Pancreas. Abdomen; Gastrointestinal Motility; GHBT; Glucose; glucose hydrogen breath test; Gram-positive bacteria; growth & development; Humans; IBS; Intestine; Intestine, Small - microbiology; Intestine, Small - physiopathology; Irritable Bowel Syndrome; Irritable Bowel Syndrome - drug therapy; Irritable Bowel Syndrome - microbiology; Irritable Bowel Syndrome - physiopathology; isolation & purification; Jejunum; Jejunum - microbiology; lactulose hydrogen breath test; LHBT; Male; Manometry; Manometry - methods; Medical sciences; methods; microbiology; Middle Aged; migrating motor complex; MMC; Motility; Neurogastroenterology; Other diseases. Semiology; physiopathology; SIBO; Small; small intestinal bacterial overgrowth; Stomach. Duodenum. Small intestine. Colon. Rectum. Anus; Studies; therapeutic use; Treatment Outcome; Infection; Human; Manometry; Jejunum; Irritable bowel syndrome; Bacteriosis; Digestive diseases; Intestinal disease; Small intestine
• ISSN: 0017-5749; 1468-3288
• DOI: 10.1136/gut.2006.108712

Background: Small intestinal bacterial overgrowth (SIBO) has been proposed to be common in irritable bowel syndrome (IBS), with altered small-bowel motility as a possible predisposing factor. Aim: To assess the prevalence of SIBO, by culture of small-bowel aspirate, and its correlation to symptoms and motility in IBS. Methods: 162 patients with IBS who underwent small-bowel manometry and culture of jejunal aspirate were included. Cultures from 26 healthy subjects served as controls. Two definitions of altered flora were used: the standard definition of SIBO (⩾105 colonic bacteria/ml), and mildly increased counts of small-bowel bacteria (⩾95th centile in controls). Results: SIBO (as per standard definition) was found in 4% of both patients and controls. Signs of enteric dysmotility were seen in 86% of patients with SIBO and in 39% of patients without SIBO (p = 0.02). Patients with SIBO had fewer phase III activities (activity fronts) than patients without SIBO (p = 0.08), but otherwise no differences in motility parameters were seen. Mildly increased bacterial counts (⩾5×103/ml) were more common in patients with IBS than in controls (43% vs 12%; p = 0.002), but this was unrelated to small intestinal motility. No correlation between bacterial alterations and symptom pattern was observed. Conclusions: The data do not support an important role for SIBO according to commonly used clinical definitions, in IBS. However, mildly increased counts of small-bowel bacteria seem to be more common in IBS, and needs further investigation. Motility alterations could not reliably predict altered small-bowel bacterial flora.