Full-Genome Analysis of Epidemic Group A Streptococcus Disease

An epidemic of more than 500 cases of severe invasive human infections caused by type emm59 group A Streptococcus (GAS) spread west to east across Canada in three years (2006 through 2009). Since emm59 GAS have heretofore been an exceedingly rare cause of disease (both pharyngeal and invasive infections), we hypothesized that the Canadian epidemic represents the emergence of a single distinct genotype with enhanced virulence attributes. To investigate the molecular genetic underpinnings of the outbreak we sequenced the and compared the genomes of 601 type emm59 organisms from invasive and pharyngeal infections.