Antimicrobial resistance in bacteria isolated from diseased horses in France.
Authors: Bourély C, Cazeau G, Jarrige N, Haenni M, Gay E, Leblond A
Journal: Equine veterinary journal
Summary
# Antimicrobial Resistance in Equine Bacterial Isolates: French Surveillance Data 2012–2016 Between 2012 and 2016, the French national surveillance network for antimicrobial resistance (RESAPATH) analysed 12,695 antibiograms from diseased horses to establish resistance patterns in major bacterial isolates and assess trends over time using generalised additive models. The five most commonly isolated bacteria were *Streptococcus* spp., *Escherichia coli*, *Pseudomonas* spp., *Staphylococcus aureus*, *Pantoea* spp. and *Klebsiella* spp., with particularly concerning resistance profiles: gentamicin resistance reached 26.9% in *Pseudomonas* and 22.1% in *S. aureus*, whilst *E. coli* showed 26.2% resistance to trimethoprim-sulfamethoxazole, and tetracycline resistance was elevated across all species studied. Most worryingly, *S. aureus* demonstrated the highest multidrug resistance rate at 22.5%, a finding of significant public health concern given its zoonotic potential, whilst resistance to third-generation cephalosporins remained below 10% in Enterobacteriaceae. Over the five-year period, resistance proportions declined in *Pseudomonas* spp. but remained static in *S. aureus*, whilst trimethoprim-sulfamethoxazole resistance increased in both *Streptococcus* spp. and *E. coli*. These findings provide valuable guidance for empirical antimicrobial selection in equine practice and underscore the necessity for continued surveillance to inform stewardship strategies that protect
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Practical Takeaways
- •Be aware that S. aureus infections in horses carry significant antimicrobial resistance patterns, particularly multidrug resistance, which can transfer to humans—inform clients and use targeted rather than broad-spectrum treatments when possible
- •Tetracycline resistance is widespread across most equine bacterial isolates, limiting its utility as empirical therapy; consider local resistance data when selecting initial antimicrobial treatments
- •Third-generation cephalosporins remain effective options for Enterobacteriaceae infections in horses, as resistance rates remain low; reserve these for serious infections to preserve their utility
Key Findings
- •S. aureus showed the highest multidrug resistance at 22.5%, with particular concern due to zoonotic potential
- •Pseudomonas spp. demonstrated 26.9% resistance to gentamicin and E. coli 26.2% resistance to trimethoprim-sulfamethoxazole
- •Third-generation cephalosporin resistance remained below 10% in all Enterobacteriaceae
- •From 2012-2016, resistance to trimethoprim-sulfamethoxazole increased in Streptococcus spp. and E. coli while decreasing in Pseudomonas spp.