Genomic Landscape and Pathogenicity Islands of Corynebacterium pseudotuberculosis Biovar Ovis: Insights from Seventeen Complete Mexican Genomes

Pathogenicity islands (PAIs) are regions of bacterial genomes that harbor genes encoding virulence factors. Identifying molecules that enhance pathogenicity is crucial for understanding the mechanisms pathogens employ to cause disease and their evolution. Corynebacterium pseudotuberculosis (C. pseudotuberculosis) is a pathogenic micro-organism that causes caseous lymphadenitis (CLA) in sheep and goats. Despite its prevalence in Mexico, its genetic material has not been analyzed for virulence factors acquired through horizontal gene transfer. Therefore, the objective of this study was to analyze the complete genome of C. pseudotuberculosis strains of Mexican origin to identify genes hosted in PAIs. Seventeen genomes were sequenced using Illumina technology. GIPSY software was used to identify the coordinates of the PAIs, and a positive selection analysis was performed. All genomes corresponded to C. pseudotuberculosis biovar ovis, and fourteen regions harboring virulence factors were identified. Additionally, five coding sequences with mutations under positive selection were identified. A comparative genetic study was conducted between the new Mexican strains and previously reported strains, using whole-genome multilocus sequence typing (wgMLST) to determine phylogenetic relationships. This work provides the complete genetic repertoire of 17 new strains and identifies 51 genes that could serve as targets in future studies.