Whole genome sequences of Streptococcus dysgalactiae isolates from cow and sheep was performed to identify virulence factor, phylogenetic relationships and host-adaptation strategies.

A total of 157 isolates were used for comparative purposes. The genome of eighty-five new isolates was sequenced by short read sequencing and comparative analysis was performed. Our findings supported SDSD as a distinct taxonomic entity and revealed several features indicating niche specialization, including the presence of unique virulence factors and distinctive metabolic pathways. SD-isolates obtained from pig, dog, horse, fish and humans were also phylogenetically delineated according to source of isolation, suggesting a branched evolution of this species, permitting adaption to multiple host-specific niches.