Analysis of Global Collection of Group A Streptococcus Genomes Reveals that the Majority Encode a Trio of M and M-Like Proteins

Abstract

While the GAS M protein has been the leading vaccine target for decades, the bacteria encode many other virulence factors of interest for vaccine development. In this work, we show that emm -like genes are encoded in a remarkable majority of GAS genomes and expressed at a level similar to that for the emm gene. In collaboration with the U.S. Centers for Disease Control, we developed molecular definitions of the different emm and emm -like gene families. This clarification should abrogate mistyping of strains, especially in the area of whole-genome typing. We have also updated the emm -typing collection by removing emm -like gene sequences and provided in-depth analysis of Mrp and Enn protein sequence structure and diversity.