Surveillance of Contagious Equine Metritis: Results of the First 5-Year Period of French Proficiency Tests for Taylorella equigenitalis Detection by Real-Time PCR.

This research article reviews the results of five years of proficiency tests in France for detecting Contagious equine metritis (CEM), a bacterial infection in horses, using real-time Polymerase Chain Reaction (PCR). The tests engaged 20 laboratories and evaluated the efficiency of different DNA extraction methods and PCR techniques, and the results showed high accuracy rates and a trend favoring direct lysis extraction over column extraction.

Creation of a Laboratory Network

• The study points out the establishment of an efficient network of approved laboratories for CEM detection by real-time PCR in France in 2017.
• The network currently consists of 20 laboratories which collaborate in this initiative.
• The objective of this network is to standardize and improve the techniques for CEM detection.

Proficiency Tests (PTs)

• The first proficiency test was conducted by the national reference laboratory for CEM in 2017 to assess the performance of the network.
• Since then, annual proficiency tests have been conducted for periodic evaluation of the laboratories’ performance.
• The present study discusses the outcomes of the five PTs that took place from 2017 to 2021.

Real-Time PCR and DNA Extraction Methods

• Five different real-time PCR methods and three DNA extraction methodologies were used during these tests.
• The results revealed a high success rate. More concisely, 99.20% of the qualitative data matched the expected results. Additionally, the R-squared of global DNA amplification calculated for each PT varied from 0.728 to 0.899, indicating a strong reliability of the tests.
• Moreover, the paper highlights the importance of DNA extraction as a key step in the analytical process. The results revealed better performance when opting for direct lysis compared to column extraction as the method of DNA extraction.
• Nonetheless, no significant statistical difference was observed when comparing the cycle threshold values achieved with direct lysis versus column and magnetic bead extractions, or when comparing magnetic bead extraction with column extraction in the most commonly used PCR technique (PCR 1).