Comparison of systemic trimethoprim-sulfadimethoxine treatment and intrauterine ozone application as possible therapies for bacterial endometritis in equine practice.
Authors: Köhne Martin, Hofbauer Lisa, Böttcher Denny, Tönissen Anna, Hegger Anna, Görgens Alexandra, Ulrich Reiner, Sieme Harald
Journal: Frontiers in veterinary science
Summary
# Editorial Summary Bacterial endometritis remains a significant reproductive challenge in equine practice, traditionally managed through systemic antimicrobial therapy, yet alternative approaches warrant investigation. Researchers randomised 30 mares with confirmed endometritis (positive uterine culture and inflammatory cytology) into three groups: intrauterine ozone insufflation (80 μg/ml, 240 ml twice at 48-hour intervals), systemic trimethoprim-sulfadimethoxine (30 mg/kg orally, twice daily for 5 days), or sterile air as control, with bacterial cultures and endometrial cytology reassessed seven days post-treatment. Both ozone and antibiotic therapy significantly reduced gram-negative bacterial growth compared to air controls, though overall bacterial clearance remained incomplete across all groups (ozone 4/9, trimethoprim-sulfadimethoxine 3/10, air 6/10 mares with persistent positive cultures). Neither treatment adversely affected endometrial histology or neutrophil populations, suggesting both options are safe for clinical use. These findings indicate that whilst systemic antibiotics and intrauterine ozone insufflation offer comparable, modest improvements over placebo, neither achieves complete bacterial resolution; practitioners should consider that additional management strategies—such as uterine lavage, improved drainage, or combination protocols—may be necessary to optimise outcomes in resistant cases of equine endometritis.
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Practical Takeaways
- •Both ozone insufflation and systemic trimethoprim-sulfadimethoxine reduce but do not eliminate bacterial endometritis in mares—expect persistent infections in approximately 30-40% of treated animals and plan follow-up culture.
- •Ozone and antibiotics are equally effective overall and both are safer than air insufflation alone, particularly for gram-negative infections; choice may depend on antimicrobial resistance patterns and access to ozone equipment.
- •Neither treatment caused detectable endometrial damage on histology, supporting their safe use in clinical practice for treating bacterial endometritis.
Key Findings
- •Bacterial growth was reduced in all treatment groups after 7 days (p < 0.05), but no significant differences between ozone, trimethoprim-sulfadimethoxine, or air control (p > 0.05).
- •Ozone and trimethoprim-sulfadimethoxine were significantly more effective than air control at reducing gram-negative bacterial growth (p < 0.05).
- •Neither ozone nor trimethoprim-sulfadimethoxine achieved complete elimination of intrauterine bacterial growth, with positive cultures remaining in 4/9 and 3/10 mares respectively.
- •No histological endometrial damage or effects on polymorphonuclear granulocyte counts were observed with either active treatment (p > 0.05).