An investigation into the suitability of a commercial real-time PCR assay to screen for Taylorella equigenitalis in routine prebreeding equine genital swabs.
Authors: Ousey J C, Palmer L, Cash R S G, Grimes K J, Fletcher A P, Barrelet A, Foote A K, Manning F M, Ricketts S W
Journal: Equine veterinary journal
Summary
# Editorial Summary Contagious equine metritis, caused by *Taylorella equigenitalis*, represents a significant threat to breeding programmes, yet traditional identification via cervical culture requires a minimum of seven days' incubation—an impractical timescale for prebreeding screening and bloodstock sales. Ousey and colleagues evaluated a commercial real-time PCR assay against conventional microbiological culture across 2,072 routine prebreeding genital swabs from Thoroughbreds, comparing both methods' ability to detect the organism's 16S DNA fragment. Results demonstrated complete concordance between positive and negative findings across both techniques, with equivalent sensitivity thresholds of 10⁻³ (three colony-forming units), whilst notably the PCR assay successfully identified *T. equigenitalis* DNA in stored samples where culture had failed—a valuable advantage for retrospective evaluation. The real-time PCR protocol delivers conclusive results within six hours compared to the seven-day minimum for culture, fundamentally transforming the practical feasibility of rapid clearance certification for breeding stock. For farriers and allied professionals supporting breeding operations, this technological shift promises streamlined compliance with Horserace Betting Levy Board requirements and sales screening protocols, though practitioners should coordinate testing protocols with their veterinary teams to ensure samples reach accredited laboratories capable of PCR analysis.
Read the full abstract on PubMed
Practical Takeaways
- •Real-time PCR screening for T. equigenitalis can replace traditional culture methods, reducing prebreeding testing time from 7+ days to under 6 hours
- •Implement commercial PCR assays for preseason HBLB Code of Practice compliance and bloodstock sales screening to meet rapid turnaround requirements
- •PCR detection reliability can be quality-assured through existing HBLB biannual laboratory testing schemes
Key Findings
- •Real-time PCR and bacterial culture showed complete concordance for positive and negative results in 2072 equine genital swabs
- •Real-time PCR completed identification in less than 6 hours compared to minimum 7 days required for bacterial culture
- •Both methods demonstrated equal sensitivity of 10^-3 (3 colony-forming units)
- •Real-time PCR successfully detected T. equigenitalis DNA from stored swabs that were culture-negative after 6 months storage at +4°C