Presence and molecular characterization of Clostridium difficile and Clostridium perfringens in intestinal compartments of healthy horses.
Authors: Schoster Angelika, Arroyo Luis Guillermo, Staempfli Henry Rolf, Shewen Patricia Elisabeth, Weese Jeffrey Scott
Journal: BMC veterinary research
Summary
# Editorial Summary Although *Clostridium difficile* and *Clostridium perfringens* are well-established triggers of equine colitis, healthy horses frequently harbour these pathogens asymptomatically—yet little is known about their distribution across the gastrointestinal tract or whether faecal sampling adequately reflects colonization in proximal compartments. Schoster and colleagues cultured intestinal contents and tissue from the stomach, small intestine, caecum, colon and rectum of clinically healthy adult horses post-mortem, using molecular characterization to identify both bacterial species and virulence-associated toxin genes (*tcdA*, *tcdB*, *cpb2*). *C. difficile* was recovered from 45% of horses with widespread distribution across compartments, whilst *C. perfringens* colonized 70% of horses but showed more proximal concentration in the small intestine and caecum; critically, faecal samples alone underestimated overall carrier status and were not representative of proximal colonization patterns. These findings challenge the assumption that faecal testing adequately screens for *Clostridium* carriage and suggest that horses harbouring these organisms in upper compartments may pose a silent risk for shedding and transmission, particularly in stressful situations that could permit translocation or proliferation. For practitioners managing horses with recurrent colic or antimicrobial-associated gastrointestinal complications, understanding that apparently healthy individuals may harbour virulent strains throughout the tract—not just distally—warrants reconsideration of diagnostic protocols and biosecurity practices around carrier animals.
Read the full abstract on PubMed
Practical Takeaways
- •Faecal culture or PCR results may underestimate or misrepresent Clostridium burden in the proximal GI tract of horses
- •Healthy horses can harbor pathogenic Clostridium species without clinical signs; presence alone does not confirm disease causation
- •Use caution interpreting single faecal samples as representative of overall Clostridium status when investigating equine colitis cases
Key Findings
- •C. difficile and C. perfringens are present in multiple intestinal compartments of healthy horses, indicating asymptomatic carrier status is common
- •Faecal samples do not accurately represent colonization patterns in proximal gastrointestinal compartments
- •Molecular characterization revealed different strain distributions across intestinal sites, suggesting compartment-specific colonization