Postvaccine Genetic Structure of<i>Streptococcus pneumoniae</i>Serotype 19A from Children in the United States

Abstract

Serotype 19A is, at present, the most important cause of IPD by replacement serotypes, and it is increasingly drug resistant. CC199 is the predominant CC among type 19A serotypes in children <5 years old. Our data suggest that some of the increase in rates of infection with serotype 19A may be due to serotype switching within certain vaccine type strains.