Small Intestinal Bacterial Overgrowth

Abstract

Small intestinal bacterial overgrowth (SIBO) is defined as the presence of an abnormally high bacterial population level in the small intestine. It is associated with various conditions of predisposing small bowel motility disorders and with neuromuscular diseases and bowel stasis resulting from surgery. The most common symptoms associated with SIBO include diarrhea, flatulence, abdominal pain and bloating. Quantitative culture of small intestinal contents and a variety of indirect tests have been used over the years in an effort to facilitate the diagnosis of SIBO. However, in the case of microbiological quantifi cation, there is a lack of clarity on the cut-offs that defi ne a positive culture and technical difficulties associated with transporting and culturing the aspirate. The indirect tests including breath tests based on bacterial metabolism of a variety of substrates have advantages over the direct culture method, in that they are simple to use, cheap and non-invasive, but there is also no breath test specifi cally validated for the diagnosis of SIBO. In conclusion, the accuracy of all current tests remains limited due to the lack of reliability of culture methods and the lack of a standard definition of the normal quantity gut flora in the small bowel. Currently, the ideal approach to treat SIBO is to treat, if possible, the underlying disease include structural problem or small bowel motility disorders, then to modify the gastrointestinal microbiota, usually with antibiotics, in a way that will result in improved symptoms. Furthermore, it can be useful to address nutritional defi ciencies that may be associated with the development of SIBO.