A study comparing the healthy and diseased equine glandular gastric microbiota sampled with sheathed transendoscopic cytology brushes.
Authors: Voss Sarah J, McGuinness David H, Weir William, Sutton David G M
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Glandular Gastric Microbiota and EGGD Equine glandular gastric disease (EGGD) remains a significant cause of poor performance in racehorses, yet the microbial community within diseased tissue has received little investigation. Voss and colleagues used 16S rRNA sequencing on samples collected via sheathed transendoscopic cytology brushes from five Thoroughbred racehorses, comparing bacterial populations in grossly normal mucosa against EGGD lesions and repeating sampling six months later. The most striking finding was a marked shift in bacterial composition: healthy tissue was dominated by Proteobacteria (46.3%), whereas EGGD lesions showed substantially higher Firmicutes (41.2% versus 20.0% in normal mucosa), with one genus—Sarcina—reaching up to 92.4% relative abundance in two affected horses. Whilst the study cannot establish whether this microbial dysbiosis causes disease or merely reflects it, the dramatic enrichment of Sarcina in lesions suggests it may serve as a useful diagnostic or prognostic biomarker for monitoring treatment response. The use of sheathed sampling brushes proved effective for obtaining mucosal samples during routine gastroscopy, making longitudinal microbiota monitoring feasible in clinical practice, though larger cohorts are needed to clarify the temporal stability of these microbial communities and their mechanistic role in EGGD pathogenesis.
Read the full abstract on PubMed
Practical Takeaways
- •EGGD is associated with altered gastric microbiota composition; monitoring Sarcina abundance could potentially aid in diagnosis or monitoring of disease progression
- •The sampling method (sheathed cytology brushes) is reliable for obtaining gastric microbiota samples during routine gastroscopy in performance horses
- •While microbiota alterations are evident in EGGD, the causative relationship remains unclear—microbiota changes may be secondary to disease rather than primary drivers
Key Findings
- •Normal glandular mucosa had higher Proteobacteria (46.3%) compared to EGGD lesions (18.9%)
- •EGGD lesions were characterized by higher Firmicutes abundance (41.2%) versus normal mucosa (20.0%)
- •Sarcina species were dramatically increased in EGGD, reaching up to 92.4% relative abundance in two horses
- •Sheathed transendoscopic cytology brushes effectively sampled gastric mucosa with detectable microbiota differences between healthy and diseased tissue