Surveillance of Contagious Equine Metritis: Results of the First 5-Year Period of French Proficiency Tests for Taylorella equigenitalis Detection by Real-Time PCR.
Authors: Petry Sandrine, Breuil Marie-France, Duquesne Fabien
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Surveillance of Contagious Equine Metritis in France Real-time PCR for detecting *Taylorella equigenitalis* is now officially recognised by the EU and World Organisation for Animal Health as equivalent to traditional culture methods, yet the clinical reliability of laboratories performing these tests had not been systematically evaluated until France established a formal quality assurance network in 2017. Between 2017 and 2021, the French national reference laboratory conducted five annual proficiency tests across 20 approved laboratories using five different real-time PCR assays and three DNA extraction protocols, with results assessed against expected positive and negative controls. Overall accuracy was remarkably high at 99.20%, though DNA extraction methodology proved influential, with direct lysis consistently producing lower cycle threshold values and better amplification curves (R-squared ranging from 0.728 to 0.899) compared to column-based extraction, particularly for the most widely used PCR assay. These findings demonstrate that whilst real-time PCR is now a reliable diagnostic tool for CEM surveillance, standardising pre-analytical procedures—especially DNA extraction methodology—across laboratory networks could optimise sensitivity and reduce inter-laboratory variation, ultimately improving confidence in test results for breeding stock certification and disease control programmes.
Read the full abstract on PubMed
Practical Takeaways
- •Veterinarians in France can rely on a validated network of 20 approved laboratories for accurate CEM diagnosis using real-time PCR, which is now the recommended standard alongside culture methods
- •When submitting samples for CEM testing, understanding that direct lysis extraction methods may provide slightly better performance than column extraction could inform laboratory selection decisions
- •Real-time PCR is now an EU and WHO-recognized diagnostic method for CEM, providing practitioners with reliable options for efficient disease surveillance and detection
Key Findings
- •A network of 20 approved French laboratories was successfully established in 2017 for CEM detection by real-time PCR with 99.20% accuracy over 5 years of proficiency testing
- •Real-time PCR is now recognized by the EU and WHO as equivalent to culture methods for CEM diagnosis
- •Direct lysis DNA extraction produced lower cycle threshold values and more favorable results compared to column and magnetic bead extraction methods
- •Overall R-squared values for DNA amplification ranged from 0.728 to 0.899 across five annual proficiency tests from 2017-2021