Group B streptococci in the female genital tract and nosocomial colonization of newborns.
In a long-term study, rates for group B streptococcus prevalence in the vagina and/or anus of nonpregnant women and pregnant women in the first trimester and in the second trimester were found as follows: 7.1%, 7.3% and 5.4% respectively. At delivery, positivity rates of 4.8% and 3.8% were found for mothers and newborns, respectively. Each pair of strains isolated from mother and newborn was of the same serotype. In 13.6% of newborns nosocomial colonization of the upper respiratory tract occurred during their stay in the maternity home. The sources were other positive newborns sharing the same boxes, the nosocomial spread proceeded in clusters. Detailed type-antigen analysis of isolates allowed identification of index cases and their direct contacts. Types Ib, Ic, II/R, III + Ic predominated. Sexual transmission was demonstrated by findings of identical serotypes in both partners: 23% of male partners of nonpregnant positive women and 9.1% of partners of pregnant positive women had positive urine samples. A control male group consisting of psychiatric sanatorium patients without sexual contact repeatedly exhibited a positivity rate of 2%.