First Isolation of Taylorella equigenitalis From Thoroughbred Horses in South Korea

Contagious equine metritis (CEM) is a highly contagious venereal disease of the equid species caused by the bacterium Taylorella equigenitalis. CEM has been reported from at least 30 countries across the world but in Asia, Japan has been the only country that had previously reported CEM, which was successfully eradicated in 2010. Since then, there had been no reports of CEM in Asia, but during the course of this study to test Thoroughbred horses in South Korea for the possible presence of CEM, a total of five strains of T. equigenitalis were isolated from four stallions and one mare which had shown no clinical signs indicative of the disease. The isolated bacteria were coccoid rod-shaped, gram negative, and were positive for oxidase, catalase and phosphatase tests. Sequencing of the 16S rDNA gene and phylogenetic analysis confirmed that the five isolates were T. equigenitalis, which showed high-sequence identity (99%–100%) with other T. equigenitalis strains. All Korean isolates were sensitive to streptomycin. This study describes the first isolation and characterization of T. equigenitalis in Thoroughbred horses raised in South Korea, representing the reintroduction of CEM into Asia.