The prevalence of heavy colonization and GBS serotypes varied significantly among our study centers. Whether this variation could in part explain geographic differences in neonatal morbidity and mortality is a hypothesis that needs further study.

Group B streptococcal (GBS) disease is a leading cause of morbidity and mortality among newborns. Many cases of newborn GBS disease can be prevented by the administration of intrapartum antibiotic prophylaxis. Current consensus guidelines for prevention of perinatal GBS disease have led to substantial declines in the incidence of GBS disease occurring in newborns <7 days of age (early-onset disease). Despite declines in the incidence of early-onset disease, approximately 20% of pregnant women are colonized with GBS at the time of labor and thus have the risk of transmitting the bacteria to their newborns. Consequently, continued and improved implementation of prevention efforts is essential. Infection control teams can contribute uniquely to prevention of perinatal GBS disease by serving as hospital champions of GBS disease prevention. In particular, teams can coordinate with administration and staff to encourage establishment and effective implementation of GBS prevention policies; facilitate improved laboratory processing of prenatal GBS screening specimens; monitor any adverse consequences of increased use of intrapartum antibiotics within the hospital; and investigate GBS cases that occur to determine whether they could have been prevented. By spearheading efforts to improve implementation of perinatal GBS disease prevention at the hospital level, hospital epidemiologists and infection control practitioners can play an important role in reducing the burden of early-onset GBS disease.