Intestinal overgrowth. Are we on the right track?

Abstract

In recent years, bacterial overgrowth has become one of the trendy diseases in social media, where "influencers" advise its investigation and treatment in the event of symptoms such as bloating, distension, diarrhea or constipation. For many years it has been known as a cause of malabsorption and even malnutrition, usually associated with anatomic alterations in the small intestine and we must always keep in mind the conditions and clinical scenarios that increase its risk. Another question would be if it can be responsible for other digestive symptoms (bloating, diarrhea) without causing this malabsorption. It seems that it could be more frequent in patients with irritable bowel syndrome and distension / functional abdominal bloating, although the great heterogeneity and in occasions the low quality of the available studies make a low level of evidence to recommend its systematic investigation in these patients.The generalization and massive use of breath test as a manner of diagnosis has contributed to the great boom of this entity, while these tests have low sensitivity and specificity, especially if lactulose is used as a substrate. Antibiotics are going to be the base of the treatment, with rifaximin being the one with the highest level of evidence. Like in other aspects of the microbiota, a better approach to this way of dysbiosis will be defining what a normal microbiota is, or better, what a normal bacterial function is.

Keywords: small intestinal bacterial overgrowth, intestinal methanogen overgrowth, irritable bowel disease.