GROUP B STREPTOCOCCUS (GBS)
Group B Streptococcus has been identified as a significant pathogenic organism for both mother and the baby. These bacteria can cause maternal-fetal infection and newborn sepsis (50% neonatal mortality rate). There is an association between maternal cervical infection, premature rupture of membranes, preterm labor and chorioamnionitis. Mothers may be GBS carriers and the carrier rate ranges from 42 to 72%. GBS remains a major cause of maternal and perinatal mortality and morbidity. Perinatal morbidity may result from direct infections of GBS and/or from the indirect effects of prematurity. A controversial aspect of maternal cultures involves a positive culture that is obtained prior to labor. Our current protocol allows treatment of this positive culture and it seems prudent to aggressively treat GBS with appropriate antibiotics following positive cultures or a strong clinical suspicion of GBS. (Refer to current ACOG guidelines)
Clinical neonatal disease may be divided into early onset and late onset disease. Early onset disease usually becomes clinically apparent during the first three days of life but may occur anytime during the first seven days of life. Late onset disease occurs after the seventh day of neonatal life and the most common clinical presentation is meningitis (85%). Mortality rates for late onset disease are lower (15-20%). The identification and treatment of maternal carriers to prevent neonatal exposure, colonization and infection with GBS is controversial. Routine cervical and vaginal cultures of all pregnant women and treatment of GBS mothers are not a simple matter and wide spread maternal screening and treatment has many problems. Currently, we are routinely screening mothers for GBS at 36 weeks of gestation by performing a vaginal culture. The current recommendations are to treat positive cultures during labor. However, in certain high-risk populations, treatment with Penicillin may be indicated at 6-week intervals. In women found to harbor GBS in the genital tract, treatment should consist of intrapartum intravenous Penicillin.
