Our studies addressed a critical knowledge gap in understanding the genomics and virulence of the bacterial pathogen
Streptococcus dysgalactiae
subsp.
equisimilis
.
S. dysgalactiae
subsp.
equisimilis
strains are responsible for a recent increase in severe human infections in some countries. We determined that certain
S. dysgalactiae
subsp.
equisimilis
strains are genetically descended from a common ancestor and that these strains can cause severe infections in a mouse model of necrotizing myositis.