Effects of rifaximin on the fecal microbiota of healthy dogs: a pilot study.
- 1Companion Animal Internal Medicine, Department of Companion Animal Clinical Sciences, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido, Japan.
- 2Food Microbiology and Food Safety Unit, Division of Preventive Veterinary Medicine, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido, Japan.
Abstract
Rifaximin is a poorly absorbed antibiotic that is used for the treatment of hepatic encephalopathy in humans. However, it is important to evaluate the effects of antibiotics on the gut microbiota because antibiotics may alter gut microbial composition. This study aimed to investigate the effects of 28 days rifaximin administration on the gut microbiota of healthy dogs. Five healthy dogs were administered rifaximin (25 mg/kg q12h) for 28 days. Fecal samples were collected from the rectum on day 0 (before rifaximin administration), day 14, and day 28. Fecal microbiota composition and diversity were evaluated by 16S rRNA gene sequencing targeting the V3-V4 region at three time points. No adverse effects, including gastrointestinal symptoms, were observed during the administration. Firmicutes was the most abundant phylum at all time points, while Fusobacteriota, Bacteroidota, and Actinobacteriota were also major phyla. No significant changes were observed in alpha diversity metrics, including amplicon sequence variants (p = 0.449), Chao1 (p = 0.241), and the Shannon index (p = 0.248), and beta diversity metrics, including weighted UniFrac distances (p = 0.471), unweighted UniFrac distances (p = 0.157), and Bray-Curtis dissimilarities (p = 0.089). No statistically significant changes in fecal microbiota alpha or beta diversity were detected following 28 days of rifaximin administration. Given the small sample size and lack of an untreated control group, these findings should be interpreted as preliminary and do not provide evidence to guide clinical use of rifaximin in dogs.
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BibTeX
@article{harada2026effects,
title = {{Effects of rifaximin on the fecal microbiota of healthy dogs: a pilot study.}},
author = {Hiroki Harada and Masahiro Tamura and Maki Kawabata and Atsushi Sakatani and Tatsuya Deguchi and Akira Fukuda and Masaru Usui and Hiroshi Ohta},
journal = {Frontiers in veterinary science},
year = {2026},
month = oct,
doi = {10.3389/fvets.2026.1761247},
url = {https://europepmc.org/article/MED/42996192},
note = {CC BY},
}
RIS
TY - JOUR
TI - Effects of rifaximin on the fecal microbiota of healthy dogs: a pilot study.
AU - Hiroki Harada
AU - Masahiro Tamura
AU - Maki Kawabata
AU - Atsushi Sakatani
AU - Tatsuya Deguchi
AU - Akira Fukuda
AU - Masaru Usui
AU - Hiroshi Ohta
PY - 2026
DA - 2026/10/23
JO - Frontiers in veterinary science
DO - 10.3389/fvets.2026.1761247
UR - https://europepmc.org/article/MED/42996192
AB - Rifaximin is a poorly absorbed antibiotic that is used for the treatment of hepatic encephalopathy in humans. However, it is important to evaluate the effects of antibiotics on the gut microbiota because antibiotics may alter gut microbial composition. This study aimed to investigate the effects of 28 days rifaximin administration on the gut microbiota of healthy dogs. Five healthy dogs were administered rifaximin (25 mg/kg q12h) for 28 days. Fecal samples were collected from the rectum on day 0 (before rifaximin administration), day 14, and day 28. Fecal microbiota composition and diversity were evaluated by 16S rRNA gene sequencing targeting the V3-V4 region at three time points. No adverse effects, including gastrointestinal symptoms, were observed during the administration. Firmicutes was the most abundant phylum at all time points, while Fusobacteriota, Bacteroidota, and Actinobacteriota were also major phyla. No significant changes were observed in alpha diversity metrics, including amplicon sequence variants (p = 0.449), Chao1 (p = 0.241), and the Shannon index (p = 0.248), and beta diversity metrics, including weighted UniFrac distances (p = 0.471), unweighted UniFrac distances (p = 0.157), and Bray-Curtis dissimilarities (p = 0.089). No statistically significant changes in fecal microbiota alpha or beta diversity were detected following 28 days of rifaximin administration. Given the small sample size and lack of an untreated control group, these findings should be interpreted as preliminary and do not provide evidence to guide clinical use of rifaximin in dogs.
SN - 2297-1769
ER -