Population Snapshot of <i>Streptococcus pneumoniae</i> Serotype 19A Isolates before and after Introduction of Seven-Valent Pneumococcal Vaccination for French Children

Abstract

Serotype 19A Streptococcus pneumoniae strains are now more frequent in French children than before the introduction of a seven-valent conjugate vaccine (PCV7). By applying multilocus sequence typing to 144 serotype 19A isolates collected before and after beginning PCV7 vaccination, we detected clonal expansion of the preexisting penicillin-intermediate sequence type 276.