Early-onset neonatal sepsis represents a diagnostic challenge, as it is a cause of neonatal mortality and morbidity. Guidelines for the prevention of group B streptococcus (GBS) infection recommend that all pregnant women must be screened for GBS carriage at the end of pregnancy, with intrapartum antibiotic prophylaxis being provided for GBS carriers. If vaginal culture is not available, GBS polymerase chain reaction (GBS-PCR) is an alternative option for this type of screening. In our unit, GBS-PCR is performed when pregnant women present to the delivery room with ongoing labor and with no results of culture GBS screening available. The main objective of this study was to evaluate the impact of the results of GBS-PCR on monitoring modifications in newborns of mothers with unknown GBS status. The secondary objectives were to confirm the feasibility of a GBS-PCR-based screening method in everyday practice and to evaluate the impact of GBS-PCR results on the modification of intrapartum antibiotic therapy in pregnant women.

A retrospective, single-center, observational study was conducted for 1 year. For dyads with GBS-PCR performed, changes concerning intrapartum antibiotic therapy and the newborn's monitoring were recorded. The feasibility of the method was evaluated by the delay between the GBS-PCR realization and the availability of the result; in addition, the number of GBS-PCR tests that could not be realized were collected.

Overall, 60 GBS-PCR samples were tested for 60 pregnant women. Results were obtained for all samples, and the median duration to obtaining the GBS-PCR results was 70 min (60.8–87.2). These results were positive for 11 (18.3 %) women and led to monitoring modifications for two infants. In total, 27 pregnant women (45 %) had modifications in their antibiotic therapy due to the GBS-PCR results.

GBS-PCR was quickly available and the results led to changes in maternal antibiotic prophylaxis and in the monitoring level of the newborns.