Antibodies to Capsular Polysaccharides of Group B Streptococcus in Pregnant Canadian Women: Relationship to Colonization Status and Infection in the Neonate

In a cohort study of 1207 pregnant women in Alberta, Canada, the serotype distributions of vaginal‐rectal group B Streptococcus (GBS) isolates were compared with all isolates from neonates with invasive GBS disease identified by population‐based surveillance. Serum concentrations of Ia, Ib, II, III, and V capsular polysaccharide (CPS)–specific IgG also were determined, according to serotype of the vaginal‐rectal colonizing GBS strain. GBS colonization was detected in 19.5% (235 of 1207) of women. Serotype III accounted for 20.6% (48 of 233) of colonizing strains available for typing but for 37% (27 of 73) of invasive isolates from neonates (P