TOPLINE

A randomized controlled trial showed that a 30-day course of rifamycin did not produce significant changes in gut antibiotic resistance gene levels in patients with cirrhosis and minimal hepatic encephalopathy (MHE). The antibiotic appeared safe, with no infections reported.

METHODOLOGY

• Antibiotic resistance is a growing concern for clinicians managing cirrhosis. Rifaximin, a non-absorbable antibiotic, has been implicated in the emergence of gut antibiotic resistance genes, particularly for vancomycin. The impact of rifamycin, a related antibiotic approved for traveler’s diarrhea, is unknown.
• Researchers conducted a clinical trial to evaluate the effect of rifamycin on gut microbial antibiotic resistance genes in 30 compensated outpatients (mean age, 65-67 years; 93% men) with cirrhosis and MHE who had no history of overt HE.
• Patients were randomly assigned to receive either rifamycin 600 mg twice daily (n = 15) or placebo (n = 15) for 30 days. 
• The team performed metagenomic sequencing on stool samples at baseline and the end of treatment. Antibiotic resistance genes were identified using the Comprehensive Antibiotic Resistance Database, and changes were tracked within and between the rifamycin and placebo groups.
• The primary endpoint was the change in stool microbiota.

TAKEAWAY

• After statistical correction, rifamycin did not significantly alter gut antibiotic resistance gene levels, either compared with placebo or from baseline within each group.
• In exploratory analyses, vancomycin, tetracycline, and nitroimidazole resistance gene levels were lower after treatment with rifamycin than at baseline. In contrast, vancomycin and tetracycline resistance gene levels rose after treatment with placebo. 
• At the end of the study, vancomycin-resistance was lower with rifamycin than with placebo, whereas the rise in Enterobacteriaceae reflected low-risk chromosomal changes rather than high-risk transmissible, plasmid-driven resistance. 
• Rifamycin appeared safe, with no infection reported during follow up. The antibiotic was associated with improved sarcopenia, but no difference in cognition was observed between two groups. Model for End-Stage Liver Disease scores and cirrhosis complications stayed stable in both groups. 

IN PRACTICE

"[The study] findings suggest that rifamycin did not promote expansion of ARO [antibiotic resistance ontology] and especially vancomycin-resistance pathways in cirrhosis," the authors wrote.

SOURCE

The study was led by Jasmohan S Bajaj, MD, Virginia Commonwealth University, Richmond. It was presented at The Liver Meeting 2026: American Association for the Study of Liver Diseases (AASLD) in Denver, Colorado.

LIMITATIONS

The study did not report any specific limitations. 

DISCLOSURES

No funding or conflicts of interest information was provided in the source poster.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.