Antimicrobial prevention of early-onset group B streptococcal sepsis: Estimates of risk reduction based on a critical literature review

Objective. To identify interventions that reduce the attack rate for early- onset group B streptococcal (GBS) sepsis in neonates. Study Design. Literature review and reanalysis of published data. Results. The rate of early-onset GBS sepsis in highrisk neonates can be red uced by administration of antibiotics. Treatment during pregnancy (antepart um prophylaxis) fails to reduce maternal GBS colonization at delivery. With the administration of intravenous ampicillin, the risk of early-onset infe ction in infants born to women with preterm premature rupture of membranes is reduced by 56% and the risk of GBS infection is reduced by 36%; addition of gentamicin may increase the efficacy of ampicillin. Treatment of women with chorioamnionitis with ampicillin and gentamicin during labor reduces t he likelihood of neonatal sepsis by 82% and reduces the likelihood of GBS i nfection by 86%. Universal administration of penicillin to neonates shortly after birth (postpartum prophylaxis) reduces the early-onset GBS attack ra te by 68% but is associated with a 40% increase in overall mortality and th erefore is contraindicated. Intrapartum prophylaxis, alone or combined with postnatal prophylaxis for the infants, reduces the early-onset GBS attack rate by 80% or 95%, respectively. Conclusions. Women with chorioamnionitis or preterm premature rupture of me mbranes and their infants should be treated with intravenous ampicillin and gentamicin. Intrapartum antimicrobial prophylaxis may be appropriate for o ther women whose infants are at increased but less extreme risk, and supple mental postpartum prophylaxis may be indicated for some of their infants. S election of appropriate candidates and prophylaxis strategies requires care ful consideration of costs and benefits for each patient.