Vaginal colonization with group B streptococcus: a study in college women.

Vaginal specimens for culture of group B Streptococcus and anonymous questionnaires were obtained from 499 college women. Group B Streptococcus was isolated from 90 (18.0%) of the participants. A selective broth medium was more sensitive for detection of vaginal isolates (85 of 493; 17.2%) than was direct inoculation of blood agar plates (44 of 466; 9.4%). The most prevalent serotypes among the isolates were type III (37.9%) and type II (25.3%). Logit analysis identified four factors associated with a higher prevalence of vaginal colonization with group B Streptococcus. These organisms were isolated significantly more often from (1) women who had an intrauterine device (50% vs. 18.6%; P less than 0.001), (2) sexually experienced women (20% vs. 7.1%; P less than 0.02), (3) women studied during the first half of the menstrual cycle (26.5% vs. 14.5%; P less than 0.01), and (4) women 20 years of age or younger (21.4% vs. 14.8%; P less than 0.05). The prevalence of colonization with group B Streptococcus was not related to sexual practices, history of venereal disease, use of oral contraceptives, presence of gynecologic symptoms, use of antibiotics, race, educational level, marital status, or history of pregnancy.