Rifaximin is associated with modest, transient decreases in multiple taxa in the gut microbiota of patients with diarrhoea-predominant irritable bowel syndrome. (2nd January 2019)

• Record Type: Journal Article
• Authors: Fodor, Anthony A.; Pimentel, Mark; Chey, William D.; Lembo, Anthony; Golden, Pamela L.; Israel, Robert J.; Carroll, Ian M.
• Is Part Of: Gut microbes. Volume 10:Isuse 1(2019)
• Page Start: 22
• Page End: 33
• Publication Date: 2019-01-02
• Subjects: Antibiotic therapy -- colonic microflora -- diarrhoea -- gastrointestinal immune response -- irritable bowel syndrome; Gastrointestinal system -- Microbiology -- Periodicals; Microbiology -- Periodicals; Intestine, Small -- Periodicals; 616.3
• DOI: 10.1080/19490976.2018.1460013
• Languages: English
• ISSNs: 1949-0984

Abstract

ABSTRACT: Rifaximin, a non-systemic antibiotic, is efficacious for the treatment of diarrhoea-predominant irritable bowel syndrome (IBS-D). Given the emerging association between the gut microbiota and IBS, this study examined potential effects of rifaximin on the gastrointestinal microbial community in patients with IBS-D. TARGET 3 was a randomised, double-blind, placebo-controlled, phase 3 study. Patients with IBS-D initially received open-label rifaximin 550 mg 3 times daily (TID) for 2 weeks. Patients who responded to the initial treatment and then relapsed were randomised to receive 2 repeat courses of rifaximin 550 mg TID or placebo for 2 weeks, with each course separated by 10 weeks. Stool samples were collected at the beginning and end of open-label treatment, at the beginning and end of the first double-blind treatment, and at the end of the study. As a secondary analysis to the TARGET 3 trial, the composition and diversity of the gut microbiota were assessed, from a random subset of patients, using variable 4 hypervariable region 16S ribosomal RNA gene sequencing. Samples from 103 patients were included. After open-label rifaximin treatment for 2 weeks, 7 taxa (e.g. Peptostreptococcaceae, Verrucomicrobiaceae, Enterobacteriaceae) had significantly lower relative abundance at a 10% false discovery rate threshold. The effects of rifaximin were generally short-term, as there was little evidence of significantly different changes in taxa relative abundance at the end of the study (up to 46 weeks) versus baseline. The results suggest that rifaximin has a modest, largely transient effect across a broad range of stool microbes. Future research may determine whether the taxa affected by rifaximin are causally linked to IBS-D. ClinicalTrials.gov identifier number: NCT01543178.