Gastrointestinal bacterial overgrowth: pathogenesis and clinical significance

Abstract

Small intestinal bacterial overgrowth (SIBO) is defined as the presence of an abnormally high number of coliform bacteria in the small bowel. It is associated with a broad range of predisposing small intestinal motility disorders and with surgical procedures that result in bowel stasis. The most common symptoms associated with SIBO include diarrhea, flatulence, abdominal pain and bloating. Quantitative culture of small bowel contents and a variety of indirect tests have been used over the years in an attempt to facilitate the diagnosis of SIBO. The indirect tests include breath tests and biochemical tests based on bacterial metabolism of a variety of substrates. Unfortunately, there is no single valid test for SIBO, and the accuracy of all current tests remains limited due to the failure of culture to be a gold standard and the lack of standardization of the normal bowel flora in the small intestine. Currently, the ideal approach to treat SIBO is to treat the underlying disease, eradicate overgrowth, and address nutritional deficiencies that may be associated with the development of SIBO.

Pilot Study on Gas Patterns of Irritable Bowel Syndrome and Small Intestinal Bacterial Overgrowth Following Ingestion of Lactulose

“…When colonic bacteria colonize the small intestine, as in SIBO, many gases are produced by fermentation of carbohydrates in the small intestine. These gases readily diffuse into the abdominal venous circulation and are transported to the lungs, where they are detected in the exhaled breath [4] [5].…”

“…Nevertheless, effectiveness of the eradication of IBS was reported, as bacterial growth was implicated in development of the syndrome [16]. Therefore, eradication therapy for IBS may be indicated based on the assumption of gastrointestinal bacterial overgrowth without an actual diagnosis of SIBO [4] [5]. In other words, even though involvement of SIBO in IBS is unclear, eradication therapy has been promoted [17].…”

Diagnosis and Treatment of Small Intestinal Bacterial Overgrowth

“…1,2 In normal condition, it found less than 10 3 organisme/mL on upper region of small intestine which mostly are gram positive organisms. 2,3 Beside the decide manifestation of signs and clinical symptoms of SIBO. 1 Characteristic things about SIBO are the excess aerob and anaerob bacteria which colonized small intestine, which an area where bacteria population is plentiful.…”

Prevalence of Small Intestine Bacterial Overgrowth in Patients With Gastrointestinal Symptoms

“…Thus, a high prevalence of overgrowth was observed in patients with functional gastrointestinal disorders, inflammatory bowel disease, liver diseases, pancreatic diseases, celiac disease, diabetes mellitus and neuromuscular diseases (3,12) . Furthermore, SIBO has been associated with certain clinical conditions including rosacea, hepatic encephalopathy, obesity, gastroparesis, Parkinson's disease, fibromyalgia, among many others (14,19,21) . It is believed that qualitative and quantitative alterations of the intestinal microbiota (dysbiosis) occur in all of these clinical conditions associated with chronic symptoms determining SIBO (5,14) .…”

“…This drug has been shown to be more effective and safer in many studies, but is not yet available in Brazil (12) . Thus, it is recognized that, currently, the emerging need to develop a systematic and consensual approach to the diagnosis and treatment of SIBO (16,19) .…”