Effects of Rifaximin on Luminal and Wall-Adhered Gut Commensal Microbiota in Mice

Marina Ferrer, Mònica Aguilera, Vicente Martinez

Research output: Contribution to journalArticleResearchpeer-review

1 Citation (Scopus)


Rifaximin is a broad-spectrum antibiotic that ameliorates symptomatology in inflamma-tory/functional gastrointestinal disorders. We assessed changes in gut commensal microbiota (GCM) and Toll-like receptors (TLRs) associated to rifaximin treatment in mice. Adult C57BL/6NCrl mice were treated (7/14 days) with rifaximin (50/150 mg/mouse/day, PO). Luminal and wall-adhered ceco-colonic GCM were characterized by fluorescent in situ hybridization (FISH) and microbial profiles determined by terminal restriction fragment length polymorphism (T-RFLP). Colonic expression of TLR2/3/4/5/7 and immune-related markers was assessed (RT-qPCR). Regardless the period of treatment or the dose, rifaximin did not alter total bacterial counts or bacterial biodiversity. Only a modest increase in Bacteroides spp. (150 mg/1-week treatment) was detected. In control conditions, only Clostridium spp. and Bifidobacterium spp. were found attached to the colonic epithelium. Rifaximin showed a tendency to favour their adherence after a 1-week, but not 2-week, treatment period. Minor up-regulation in TLRs expression was observed. Only the 50 mg dose for 1-week led to a significant increase (by 3-fold) in TLR-4 expression. No changes in the expression of immune-related markers were observed. Rifaximin, although its antibacterial properties, induces minor changes in luminal and wall-adhered GCM in healthy mice. Moreover, no modulation of TLRs or local immune systems was observed. These findings, in normal conditions, do not rule out a modulatory role of rifaximin in inflammatory and or dysbiotic states of the gut.

Original languageEnglish
Article number500
Pages (from-to)1-19
Number of pages19
JournalInternational journal of molecular sciences
Issue number2
Publication statusPublished - 2 Jan 2021


  • Animals
  • Anti-Bacterial Agents/pharmacology
  • Bacteria/classification
  • Colon/drug effects
  • Dysbiosis
  • Female
  • Gastrointestinal Microbiome/drug effects
  • Gene Expression/drug effects
  • Gut commensal microbiota
  • Host-bacterial interaction systems
  • Immune mark-ers
  • In Situ Hybridization, Fluorescence
  • Intestinal Mucosa/drug effects
  • Mice, Inbred C57BL
  • Protein Isoforms/genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • Rifaximin
  • Rifaximin/pharmacology
  • Toll-Like Receptors/genetics
  • Toll-like receptors


Dive into the research topics of 'Effects of Rifaximin on Luminal and Wall-Adhered Gut Commensal Microbiota in Mice'. Together they form a unique fingerprint.

Cite this