Population Snapshot of Emergent<i>Streptococcus pneumoniae</i>Serotype 19A in the United States, 2005

Abstract

PCV7 ineffectiveness against serotype 19A, antibiotic resistance, clonal expansion and emergence, and capsular switching have contributed to the genetic diversity of 19A and to its emergence as the predominant invasive pneumococcal serotype in the United States.