Type-Specific Serum Antibodies against Group B Streptococci among Pregnant Women: Relation to Urogenital Carriage and Age

Abstract

Serum levels of type-specific antibodies against group B streptococci (GBS) were investigated in 53 pregnant urogenital carriers of GBS and in 20 pregnant non-carriers. The distribution of serotypes of GBS isolated from the urogenital tract of the 53 culture-positive patients was: type Ia, 20 patients (38%), type II, 10 (19%), and type III, 23 (43%). Antibodies to GBS types Ia, Ib, II and III were quantitated by the use of radiolabelled protein A. It was found that the pregnant GBS carriers had in general higher levels of type-specific antibodies to GBS than non-carriers, irrespective of the type of GBS harboured in the urogenital tract. Furthermore, it was found that younger GBS carriers (20 to 29 yr of age) had higher serum levels of type-specific antibodies than older carriers (30 to 39 yr), a difference that did not occur among the non-carriers.