Limited prolonged effects of rifaximin treatment on irritable bowel syndrome-related differences in the fecal microbiome and metabolome

Abstract

Irritable bowel syndrome (IBS) is a chronic functional disorder and its development may be linked, directly and indirectly, to intestinal dysbiosis. Here we investigated the interactions between IBS symptoms and the gut microbiome, including the relation to rifaximin (1200 mg daily; 11.2 g per a treatment). We recruited 72 patients, including 31 with IBS-D (diarrhea), 11 with IBS-C (constipation), and 30 with IBS-M (mixed constipation and diarrhea) and 30 healthy controls (HCs). Of them, 68%, 64%, and 53% patients with IBS-D, IBS-C, and IBS-M, respectively, achieved 10–12 week-term improvement after the rifaximin treatment. Stool samples were collected before and after the treatment, and fecal microbiotic profiles were analyzed by deep sequencing of 16S rRNA, while stool metabolic profiles were studied by hydrogen 1-nuclear magnetic resonance (1H-NMR) and gas chromatography–mass spectrometry (GC-MS). Of 26 identified phyla, only Bacteroidetes, Firmicutes, Proteobacteria, and Actinobacteria were consistently found in all samples. Bacteroidetes was predominant in fecal samples from HCs and IBS-D and IBS-M subjects, whereas Firmicutes was predominant in samples from IBS-C subjects. Species richness, but not community diversity, differentiated all IBS patients from HCs. Metabolic fingerprinting, using NMR spectra, distinguished HCs from all IBS patients. Thirteen metabolites identified by GC-MS differed HCs and IBS patients. However, neither metagenomics nor metabolomics analyses identified significant differences between patients with and without improvement after treatment.

Systematic review with meta‐analysis: the efficacy of prebiotics, probiotics, synbiotics and antibiotics in irritable bowel syndrome

“…Given the drugs beneficial effects in patients with IBS with diarrhoea, this would seem paradoxical. Studies that have evaluated the effect of rifaximin on the microbiome, show that any changes are limited, and are not sustained . Although the limited research regarding rates of C. difficile infection and microbial resistance are reassuring, continued monitoring of patients receiving repeated courses of the drug will be required.…”

American College of Gastroenterology Monograph on Management of Irritable Bowel Syndrome

“…Studies have revealed that a 2-week course of treatment causes modest, but detectable, changes in microbial profiles of the feces (144,145). Other research studies evaluating fecal microbial profiles from IBS patients demonstrated that rifaximin effects on the microbiota were limited and not sustained (145)(146)(147).…”

Relief of irritable bowel syndrome by fecal microbiota transplantation is associated with changes in diversity and composition of the gut microbiota

“…There is emerging evidence that gut microbiota play an important role in the development of IBS. 1 Recent reports have indicated that the composition of gut microbiota differs between patients with IBS and healthy individuals [2][3][4] and contributes to IBS pathophysiology. [5][6][7][8] Treatment with antibiotics, such as rifaximin, relieves global IBS symptoms without causing constipation, suggesting that there is a direct relationship between microbiota and IBS.…”