Antibiotic treatment of parturient women colonized with group B streptococci.

A prospective study was conducted among third-trimester parturient women with cervical or urethral colonization with group B streptococci to determine the influence of antibiotic treatment on subsequent colonizations among their infants. Cultures were obtained from dry swabs inoculated directly onto selective blood agar media containing neomycin and naladixic acid. Seventy-four women were found to be colonized among 1,098 cultured (7%). A significant reduction in colonization was noted among mothers treated with ampicillin within three weeks of completion of therapy. This difference was no longer apparent at delivery. There was likewise no difference in the colonization rate of infants in the treatment and no-treatment groups. The data suggest that additional measures must be undertaken to prevent maternal recolonization.