Group B Streptococcus (GBS) remains the leading cause of neonatal sepsis and meningitis in industrialized countries. Whereas the use of intrapartum antibiotic prophylaxis has led to a significant decline in early-onset sepsis, the incidence of late-onset sepsis has remained unchanged. Whether late-onset sepsis usually originates from established mucocutaneous GBS colonization of the infant or whether it results from an acute exogenous GBS infection remains controversial. Here we report on twins who both twice developed GBS sepsis in a strikingly parallel fashion, with both instances originating from a single hypervirulent GBS clone. Factored together, the presentation as cervical soft tissue infection in both cases, the synchronicity of the episodes, and the detection of GBS DNA in breast milk all strongly suggest an enteral mode of transmission with a short incubation period.

• The prediction of prepartum GBS screening for intrapartum colonization status has not been well studied. • Longitudinal studies of GBS screening are needed for screening program evaluations and vaccine development. What is New: • The rate of GBS screening has improved over 10 years, and intrapartum GBS colonization prediction was accurate. • Serotype distribution was stable and suggests the potential long-term efficacy of GBS vaccines.