ABSTRACT
Small intestinal bacterial overgrowth (SIBO) corresponds to the excessive growth of inherent small intestinal flora or the growth of colonic type flora in the small intestine, causing symptoms as a result of early bacterial fermentation, malabsorption, and inflammation. Alteration in the anatomy of the GI tract that leads to stagnation of the intestinal contents such as strictures (radiation, surgical, or Crohn’s disease), blind loops, and diverticulae predisposes to SIBO. Surgical resection of the ileocecal valve promotes bacterial overgrowth in the small intestine. The exact prevalence of SIBO is unknown due to the lack of consensus in definition, diagnostic criteria, and testing methods. Similarly, SIBO has vague and heterogeneous presentations and its symptoms often overlap with other conditions such as irritable bowel syndrome (IBS) or celiac disease, which makes defining the epidemiology challenging. Symptoms of SIBO are non-specific and result mainly from excessive fermentation of carbohydrates, bacterial consumption of nutrients, and malabsorption of macro- and micronutrients.
