Emergent Invasive Group A Streptococcus dysgalactiae subsp. equisimilis, United States, 2015–2018

Abstract

The term group A Streptococcus is considered synonymous for the species Streptococcus pyogenes. We describe an emergent invasive S. dysgalactiae subspecies equisimilis lineage that obtained the group A antigen through a single ancestral recombination event between a group C S. dysgalactiae subsp. equisimilis strain and a group A S. pyogenes strain.

Keywords

• invasive group A streptococci
• Streptococcus dysgalactiae
• Streptococcus pyogenes
• Streptococccus equisimilis
• Lancefield group A antigen
• multilocus sequence type