Fecal microbiota of horses with colitis and its association with laminitis and survival during hospitalization.
Authors: Ayoub Cosette, Arroyo Luis G, MacNicol Jennifer L, Renaud David, Weese J Scott, Gomez Diego E
Journal: Journal of veterinary internal medicine
Summary
# Editorial Summary Dysbiosis in equine colitis appears multifactorial, with pathogenic taxa including Enterobacteriaceae, Lactobacillus, Streptococcus and Enterococcus significantly enriched compared to healthy horses, whilst beneficial fibre-fermenting bacteria such as Faecalibacterium, Ruminococcaceae and Lachnospiraceae are depleted. Ayoub and colleagues analysed faecal microbiota from 36 healthy and 55 hospitalised colitis cases using 16S rRNA sequencing to identify microbial signatures associated with secondary laminitis development and survival outcomes. Whilst colitis cases developing laminitis showed enrichment of Enterobacteriaceae, Streptococcus and Lactobacillus specifically, and non-surviving horses exhibited additional Pseudomonas and Enterococcus dominance, the microbiotal differences between these outcome groups were modest—suggesting that microbiota composition alone may not be a strong predictor of laminitis or mortality during hospitalisation. These findings highlight that whilst gross dysbiosis characterises equine colitis and likely contributes to systemic complications, the specific bacterial taxa present may be less clinically discriminatory than the overall magnitude of dysbiosis itself, indicating that therapeutic strategies should focus on restoring general microbial diversity and beneficial fibre-fermenting populations rather than targeting individual pathogenic species.
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Practical Takeaways
- •Microbiota composition differs significantly between healthy and colitic horses, but these differences have limited predictive value for laminitis development or survival during hospitalization
- •While certain bacterial taxa (particularly Enterobacteriaceae) are associated with adverse outcomes in colitis, microbiota analysis alone appears insufficient as a prognostic indicator for individual cases
- •Therapeutic strategies targeting microbiota restoration in colitic horses may focus on restoring beneficial taxa (Faecalibacterium, Ruminococcaceae, Lachnospiraceae) rather than preventing laminitis or improving survival
Key Findings
- •Colitis horses showed enrichment of Enterobacteriaceae, Lactobacillus, Streptococcus, and Enterococcus compared to healthy horses (LDA >3; P <0.05)
- •Healthy horses were enriched in Treponema, Faecalibacterium, Ruminococcaceae, and Lachnospiraceae (LDA >3; P <0.05)
- •Non-surviving colitis horses had enrichment of Enterobacteriaceae, Pseudomonas, Streptococcus, and Enterococcus compared to survivors
- •Microbiota differences between colitis horses with and without laminitis were minor (AMOVA; P >0.05)