Prevention of Early-onset GBS Sepsis: Evaluation of a Changing Paradigm

Abstract

Prevention of neonatal sepsis caused by group B streptococcus (GBS) is the goal of current, prophylactic strategies. A recent population-based surveillance study has shown that antepartum screening for GBS was 50% more effective than the risk-based approach at preventing perinatal GBS.1 This study led to the updated guidelines published by the CDC, which provide recommendation for universal prenatal culture-based screening for GBS colonization as well as instruction on specimen collection, culture processing, and susceptibility testing and prophylaxis regimens for women with penicillin allergy. 2Coincident with active prevention efforts in the 1990's, the incidence of early-onset GBS decreased from two to three cases per 1000 live births to 0.5 cases per 1000 live births (1). In this issue of the Journal of Perinatology, studies by Riley et al.3 as well as Pinto et al. 4 evaluated the effectiveness of and residual problems associated with the culture-based and risk-based GBS prevention strategies.Riley et al. 3 examined compliance with intrapartum antibiotic prophylaxis, which they found to be dependent on the practice setting and the prevention strategy employed. Several of the problems they identified will no longer be an issue when birthing centers replace the risk-based strategy with the culture-based GBS prevention strategy. In Riley's study, for those women managed with the culture-based strategy, almost 10% failed to have documentation of GBS screening-culture results at the time of delivery and up to 6% of the GBS screening cultures were obtained in the first trimester. Of women whose screening cultures were positive for GBS, 30 to 46% were treated with antibiotics for less than the optimal 4 hours before delivery. In Riley's estimation, 50% of those women could have received antibiotics at least 4 hours before delivery. These authors recommended that patient education about GBS screening-culture results and strict attention to maternal GBS culture status upon presentation in labor would improve compliance with antibiotic administration within 4 hours of delivery.Pinto et al. 4 reviewed 94 cases of early-onset GBS admitted to two regional level III NICUs from 07/92 through 12/01. Of these infants, 50 (53%) were born to women whose GBS colonization status was (i) unknown and who had no identified risk factors or (ii) whose GBS screening culture was reported as negative. The majority of missed opportunities for appropriate administration of intrapartum antibiotics were attributed to: failure to perform or faulty performance of cultures, unreliable culture results, and antibiotic administration for less than 4 hours before delivery.Few studies to date have evaluated implementation and efficacy of CDC protocol for management of infants born to women colonized with GBS. Pinto recommends further evaluation of adjunctive postnatal prophylaxis, which in reality would represent early treatment. 4 In his cohort, such postnatal ''prophylaxis'' would not have been effective, as disease presented clinically at 2.1±1....