Streptococcus equi culture prevalence, associated risk factors and antimicrobial susceptibility in a horse population from Colombia.

Authors: Jaramillo-Morales Camilo, Gomez Diego E, Renaud David, Arroyo Luis G

Journal: Journal of equine veterinary science

DOI: 10.1016/j.jevs.2022.103890 PubMed: 35124153Log in to save

Summary

Streptococcus equi remains a significant pathogen in Colombian horse populations, with a 15% prevalence of colonisation detected in guttural pouch swabs across 137 horses sampled from 15 farms, comprising 13.5% *S. equi* subsp. *equi* and 1.5% *S. equi* subsp. *zooepidemicus*. Using endoscopic sampling, culture, PCR sequencing and BLAST confirmation, researchers identified travel history as a key risk factor for detection, whilst increasing age appeared protective—each additional year reducing the odds of positive identification. Antimicrobial susceptibility testing revealed encouraging sensitivity to penicillin, ceftiofur and trimethoprim-sulphamethoxazole, though all isolates demonstrated resistance to enrofloxacin and oxytetracycline. The high prevalence and apparent endemicity of *S. equi* in this population has important implications for biosecurity protocols on Colombian farms, particularly regarding movement of young stock and recently travelled horses, whilst antimicrobial selection should favour β-lactams or trimethoprim-sulphonamides rather than fluoroquinolone or tetracycline approaches if treatment is warranted.

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Practical Takeaways

•Young horses and those with recent travel history should be considered higher risk for S. equi infection; consider enhanced screening and isolation protocols for these animals
•Penicillin, ceftiofur, or trimethoprim-sulfamethoxazole are reliable antimicrobial choices for S. equi infections in this region; avoid enrofloxacin and oxytetracycline due to reported resistance
•S. equi is endemic in Colombian horse populations, so veterinary practitioners should maintain high clinical suspicion and implement biosecurity measures to prevent transmission between farms

Key Findings

•S. equi culture prevalence in guttural pouches was 15% (13.5% S. equi subsp. equi and 1.5% S. equi subsp. zooepidemicus) in a Colombian horse population
•History of travel was significantly associated with S. equi detection, while each 1-year increase in age decreased the risk of detection
•All isolates were susceptible to trimethoprim-sulfamethoxazole, ceftiofur, and penicillin, but resistant to enrofloxacin and oxytetracycline
•S. equi appears to be endemic in the tested Colombian population with high prevalence in younger horses

Conditions Studied

streptococcus equi infections. equi subsp. equis. equi subsp. zooepidemicusguttural pouch disease

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