Geoepidemiological hints about Streptococcus pyogenes strains in relationship with acute rheumatic fever

Group A . Streptococcus (GAS) strains are lately classified on the basis of sequence variations in the . emm gene encoding the M protein, but despite the high number of distinct . emm genotypes, the spectrum of phenotypes varying from invasive suppurative to non-suppurative GAS-related disorders has still to be defined. The relationship of GAS types with the uprising of acute rheumatic fever (ARF), a multisystemic disease caused by misdirected anti-GAS response in predisposed people, is also obscure. Studies published over the last 15. years were retrieved from PubMed using the keywords: ". Streptococcus pyogenes" or "group A . Streptococcus" and "acute rheumatic fever": the prevalence of peculiar . emm types across different countries of the world is highly variable, depending on research designs, year of observation, country involved, patients' age, and gender. Most studies revealed that a relatively small number of specific . emm/M protein types can be considered "rheumatogenic", as potentially characterized by the possibility of inducing ARF, with remarkable differences between developing and developed countries. The association between . emm types and post-streptococcal manifestations is challenging, however surveillance of disease-causing variants in a specific community with high rate of ARF should be reinforced with the final goal of developing a potential primary prophylaxis against GAS infections.