Symptoms and causes of small intestinal bacterial overgrowth

Small intestinal bacterial overgrowth (SIBO) is a condition in which symptoms are caused by changes in the composition and number of bacteria in the small bowel—most commonly streptococci, Bacteroides species, Escherichia coli and Lactobacillus speciesQuigley, 2020.

Common symptoms of SIBO include bloating, diarrhoea, excessive flatulence, nausea and abdominal pain or discomfort. The prevalence of SIBO is unknown. It can cause maldigestion and malabsorption of nutrientsQuigley, 2020.

SIBO is often caused by intestinal stasis due to anatomical abnormalities (including strictures), jejunal diverticulosis, motility disorders, or various operations that create blind loopsQuigley, 2020. Less common causes of SIBO include hypochlorhydria (including proton pump inhibitor use), chronic pancreatitis, cirrhosis, scleroderma, immune compromise or advanced ageQuigley, 2020.