Towards European harmonisation of contagious equine metritis diagnosis through interlaboratory trials.
Authors: Petry Sandrine, Breuil Marie-France, Duquesne Fabien, Laugier Claire
Journal: The Veterinary record
Summary
# Editorial Summary: Contagious Equine Metritis Diagnosis — Moving Towards European Standards Contagious equine metritis (CEM) remains a notifiable disease of significant breeding importance, yet diagnostic inconsistency across European laboratories has hampered effective disease control and trade compliance. Two interlaboratory trials coordinated 24 European institutions (including 22 National Reference Laboratories) to evaluate and standardise both culture and PCR methodologies using artificially contaminated swabs, with particular attention to distinguishing *Taylorella equigenitalis* (the CEM pathogen) from the morphologically similar *T. asinigenitalis*. PCR demonstrated superior specificity and sensitivity compared to traditional culture methods across both trials, with notably improved culture performance in the second trial, suggesting that participant expertise can be meaningfully enhanced through structured benchmarking exercises. The findings support acceptance of PCR as a validated diagnostic tool for CEM whilst simultaneously highlighting the need for development of more selective and metabolically optimised culture media to strengthen bacteriological diagnosis in laboratories with limited molecular capacity. Regular interlaboratory trials emerge as essential quality assurance mechanisms, particularly given that cultural competency and technical standardisation directly impact the diagnostic reliability upon which trade restrictions and breeding decisions depend.
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Practical Takeaways
- •PCR should be the preferred diagnostic method for CEM as it provides better accuracy than culture; discuss testing method selection with your diagnostic laboratory
- •Regular participation in interlaboratory trials and quality assurance programs can improve your laboratory's diagnostic performance and consistency
- •Request PCR-based CEM testing when possible to reduce the risk of false negatives and ensure reliable results for breeding soundness certification
Key Findings
- •PCR demonstrated superior specificity and sensitivity compared to culture methods for CEM diagnosis across 24 European laboratories
- •Culture method performance improved between the first and second interlaboratory trial, indicating that laboratory expertise can be enhanced through regular comparative testing
- •Taylorella asinigenitalis can be misidentified as T. equigenitalis, creating diagnostic challenges
- •Current culture media are not adequately selective or optimized for T. equigenitalis metabolism, limiting bacteriological diagnostic reliability