Comparison of inter- and intraserotype variation of group A Streptococci. Streptococcus pyogenes

This study examined the relationship between strain genotypes and patient phenotypes of the group A Streptococcus serotype M3 organisms to help understand the underlying mechanisms of virulence. M3 strains have been studied extensively due to the fact that they cause a disproportionate number of invasive diseases including necrotizing fasciitis (flesh eating), bacteremia, and toxic shock and have a higher rate of lethal infections. All sequences were compared to identify a set of SNPs that were found in the core metagenome (conserved in all strains and lacking foreign sequences such as prophage). Comparison of two clinical types, the carrier and invasive strains, demonstrated that allelic variation due to polymorphisms resulted in phenotypic differences although no uniformly present SNP was found that contributed to either phenotype. An expression microarray experiment has been published in GEO in GSE3966.