Failure of penicillin to eradicate the carrier state of group B Streptococcus in infants.

Serial cultures were obtained from 12 patients being treated with a form of penicillin for group B streptococcal disease or asymptomatic colonization. These cultures were collected prior to initiation of therapy, during therapy, and at the end of the treatment period. Pencillin eradicated GBS from the involved system (blood, CSF, bone, and joint). Cultures remained positive from at least one of three carrier sites (throat, umbilicus, and rectum) in 70% of patients cultured between days one and eight of treatment and 66% between days 10 and 21. These data demonstrate the failure of penicillin to eradicate GBS from mucous surfaces of young infants.