Antimicrobial Resistance in Equine Reproduction.
Authors: Malaluang Pongpreecha, Wilén Elin, Lindahl Johanna, Hansson Ingrid, Morrell Jane M
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary: Antimicrobial Resistance in Equine Reproduction Antimicrobial resistance (AMR) poses an emerging challenge in equine breeding programmes, particularly within the reproductive tract and artificial insemination protocols. Pongpreecha and colleagues conducted a comprehensive literature review examining AMR prevalence in equine uterine and vaginal environments over the past two decades, with specific emphasis on the role of prophylactic antibiotics routinely added to semen extenders during collection and processing. The review identified concerning patterns: pathogenic bacteria including *Klebsiella pneumoniae*, *Escherichia coli*, and *Pseudomonas aeruginosa*—commonly harbouring antimicrobial-resistant strains—contaminate semen during collection from the reproductive tract and processing stages, competing with spermatozoa for nutrients and compromising sperm quality through metabolic toxins. Whilst current legislation mandates antibiotic inclusion in extenders as a control measure, this practice directly contradicts prudent antimicrobial stewardship guidelines and may itself impair sperm viability depending on agent selection and concentration. The authors argue for a paradigm shift towards physical separation technologies (particularly colloid centrifugation) as viable alternatives that eliminate bacteria without the dual pitfalls of selecting for resistance and damaging gamete function—findings with significant implications for breeding facility protocols, regulatory frameworks, and long-term herd fertility outcomes across the industry.
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Practical Takeaways
- •Review your semen collection and processing protocols to minimize bacterial contamination at critical control points, recognizing that bacteria from the reproductive tract are routinely transferred to semen
- •Question routine antibiotic addition to semen extenders—antibiotics may harm sperm quality and contribute to resistance development; consider sensitivity testing and selective use only when needed
- •Explore alternative bacterial removal methods such as colloid centrifugation to replace or reduce reliance on antimicrobial semen additives while maintaining fertility outcomes
Key Findings
- •Antimicrobial resistance in equine reproductive tracts has been reported worldwide across Europe, India, and the United States over the last 20 years
- •Bacteria colonizing reproductive mucosa contaminate semen during collection and processing, competing with spermatozoa and producing metabolic byproducts detrimental to sperm quality
- •Antibiotics added to semen extenders during processing may impair sperm quality and contradict prudent antimicrobial use guidelines that recommend therapeutic use only after bacterial sensitivity testing
- •Physical separation of spermatozoa from bacteria through methods such as colloid centrifugation offers potential as an alternative to routine antibiotic addition