Group A Streptococcus (GAS) causes a wide array of infections ranging from mild to serious and even life threatening. Epidemic strains of GAS have enhanced virulence; however, the molecular events that allow for widespread dissemination of this disease are not fully understood. In this episode, James Musser discusses the identification of genetic changes that cause increased virulence in epidemic strains of GAS. Extensive genomic sequencing of pre- and post-epidemic strains revealed the presence of SNPs within a regulatory element that increase the expression of two potent bacterial toxins. The results of this study provide insight into the molecular drivers of the emergence of epidemic GAS strains.
The identification of the molecular events responsible for strain emergence, enhanced virulence, and epidemicity has been a long-pursued goal in infectious diseases research. A recent analysis of 3,615 genomes of serotype M1 group A
Luchang Zhu, Randall J. Olsen, Waleed Nasser, Stephen B. Beres, Jaana Vuopio, Karl G. Kristinsson, Magnus Gottfredsson, Adeline R. Porter, Frank R. DeLeo, James M. Musser