Gut Microbiota: Modulate its Complexity to Restore the Balance

The importance of the gut microbiota to health is becoming more widely appreciated. The range of commensal microorganisms in healthy individuals and in patients with a variety of digestive diseases is under active investigation, and evidence is accumulating to suggest that both the diversity and balance of bacterial species are important for health. Disturbance of the balance of microorganisms – dysbiosis – is associated with obesity and a variety of diseases. Restoring the balance by modulating the microbiota through diet, probiotics, or drugs is now being developed as a potential treatment for digestive diseases. Rifaximin has been shown to increase levels of beneficial bacterial species without perturbing the overall composition of the microbiota in patients with a variety of digestive diseases, making it a ‘eubiotic’ rather than an antibiotic. Rifaximin has demonstrated clinical benefit in the treatment of symptomatic uncomplicated diverticular disease, where changes in the colonic microbiota contribute to the pathogenesis of this disease. Modulating the microbiota is also a promising treatment for some types of irritable bowel syndrome (IBS) that have been linked to an overgrowth of coliform and Aeromonas species in the small intestine. Rifaximin has demonstrated efficacy in relieving symptoms and reducing relapses in diarrhoeal IBS in the TARGET-1, 2, and 3 trials, without reducing microbial diversity or increasing antimicrobial resistance. While many aspects of the balance of gut microbiota in disease are not yet fully understood, the new understanding of rifaximin as a modulator of gut microbiota may open up new treatment options in digestive disease.