Small Intestinal Bacterial Overgrowth of Colonic-Type Carbohidrates Fermentative Bacteria in Cirrhotic Patients

Purpose: Small intestinal bacterial overgrowth (SIBO) is a clinical condition characterized by abnormally high colonic-type bacteria in the small intestine, exceeding 106 organisms/mL. In non cirrhotic patients, SIBO is associated with the presence of symptoms related to malabsorption and gas production (end product of carbohydrates fermentation). A role of small bowel bacteria has been hypothesized in the pathogenesis of hepatic encephalopathy (HE) and spontaneous bacterial peritonitis (SBP) in cirrhotics. This study to assess SIBO prevalence in cirrhotic patients. Methods: Thirthy (30) HCV-cirrhotic pts (10 Child A; 10 Child B; 10 Child C) were consecutively enrolled and submitted to H2-lactulose breath test (LBT). 30 non cirrhotics patients were used as controls. SIBO diagnosis was based on LBT positivity criteria (two distinct peaks, consisting of two consecutive H2 values >10 p.p.m. above the basal value after 10 g lactulose ingestion). Results: 18 out of 30 cirrhotics (60%) had a positive LBT vs 1 out of 30 controls (3.3%); P < 0.05. Among cirrhotics, a significative difference was observed in the different Child group: 20% in Child A, 50% in Child B, 80% in Child C. Conclusion: Cirrhotics have a significant prevalence of SIBO compared to controls. SIBO prevalence was associated to severity of cirrhosis. Lactulose administration could be a good substrate for the growth in the small bowel of fermentative colonic-type bacteria. A role of SIBO presence in HE and SBP has to be fully evaluated.