Development of the multilocus sequence typing (MLST) scheme for molecular typing of Trueperella pyogenes

Trueperella pyogenes is a Gram-positive bacterium causing purulent opportunistic infections in livestock and wild animals. Despite its broad host distribution and significant economic impact on the livestock industry, the global diversity and population structure of T. pyogenes remain poorly characterised. Research on the epidemiology of T. pyogenes infections requires the use of relevant typing methods, which are helpful in the differentiation of strains of diverse origins. This study aimed to develop a multilocus sequence typing (MLST) scheme for T. pyogenes that allows for the worldwide comparison of available sequence data. The MLST scheme for T. pyogenes was developed based on the sequences of seven housekeeping genes (adk, gyrB, leuA, metG, recA, tpi and tuf) and applied to study data for 114 T. pyogenes isolates (58 T. pyogenes clinical isolates, two reference strains and 54 whole genome sequences of this species available in the public database). We identified 91 sequence types (STs) among 114 isolates, indicating that T. pyogenes contains a genetically diverse population. Six clonal complexes were distinguished among these STs. Some correlation was observed between STs and host species, but not in relation to the geographical locations of isolates. Here, we designed the MLST scheme for T. pyogenes and evaluated its usefulness for the assessment of genetic variation of isolates. Our study, with reproducible methodology and comparable results, established a solid frame for the differentiation and phylogenetic analysis of T. pyogenes isolates, which will help to improve our understanding of the epidemiology of infections caused by this pathogen.