In order to prevent the neonatal infection of group B streptococcus (GBS), vaginal cultures and anti-GBS type III antibody in sera were investigated in pregnant women. Antibodies in sera of the cases with GBS infection were also measured.
Vaginal cultures were carried out in 1199 cases. GBS was isolated in 129 cases and the colonization rate was 10.8%. GBS type III was isolated in 18 cases (14.0%), type Ia in 30 (23.3%) and type IIIR in 16 (12.4%).
Antibody levels to GBS type III were detected with the enzyme linked immunosorbent assay (ELISA) in sera of 3548 pregnant women in the first or second trimester. The antibody levels ranged from 0 to 47.8μg/ml and the mean±SD was 4.9±4.4μg/ml.
Antibody levels of GBS type III colonized women were not so high as expected. We experienced 3 cases of GBS type III neonatal systemic infection, and measured antibody levels in the sera of these patients at the onset. These were low and all cases under 10μg/ml.
We suggest that on the full term neonates whose mother's antibody levels are more than 10μg/ml, GBS infections will be preventable.