Core genome multilocus sequence typing analysis of Finnish Taylorella equigenitalis isolates.

The research article focuses on identifying the specific genotypes of Taylorella equigenitalis, a bacteria causing contagious equine metritis (CEM) in Finland, using core genome multilocus sequence typing (cgMLST) to enhance the understanding of the spread and evolution of this disease in the Finnish horse population.

Investigating Taylorella equigenitalis in Finland

• The focus of the research paper revolves around T. equigenitalis, a bacterium that causes contagious equine metritis, a sexually transmitted infection in horses which was first detected in Finland in 1992. The study aims to genotype Finnish T. equigenitalis isolates to provide a better understanding of how this bacteria operates within the Finnish horse population.

Methods and Testing

• Researchers used whole genome sequencing (WGS) and subsequent local ad hoc core genome multilocus sequence typing (cgMLST) on 34 T. equigenitalis isolates from 24 horses collected between 1992 and 2021. The cgMLST targeted 1259 loci, specific positions in the genome.
• From the data obtained, researchers extracted classical MLST profiles and discovered three new MLST types – ST81, ST82 and ST83, as well as four previously known sequence types – ST16, ST17, ST50, and ST63.

cqMLST and MLST Analysis

• A cqMLST minimum spanning tree analysis, using a 12 allele difference as a threshold, resulted in five clusters and three singletons. These clusters were consistent with the MLST-defined groups, except for the ST83 isolates which were divided into two clusters.
• Despite the benefits of MLST to define groups, the higher discriminatory power of cqMLST proved useful for differentiating between isolates of the same MLST type, because every isolate had a unique core genome ST.

Implications for Future Research and Understanding

• Findings suggest that cgMLST has potential to be a standardized typing method for T. equigenitalis in the future.
• Furthermore, the study contributes to worldwide phylogenetic and spatio-temporal analyses required for a more complete understanding of the epidemiology of the T. equigenitalis bacterium.