Neonatal meningitis and recurrent bacteremia with group B Streptococcus transmitted by own mother's milk: A case report and review of previous cases

This article reports a case of neonatal meningitis and recurrent bacteremia caused by group B Streptococcus (GBS) transmitted via the mother's milk. A 3-day-old neonate suffered early-onset meningitis due to GBS, from which he recovered after antibiotic treatment for 4 weeks. GBS was not detected in the vaginal or stool cultures of the neonate's mother before delivery. However, 4 days after treatment of GBS meningitis, the neonate developed GBS bacteremia. As the mother repeatedly showed signs of mastitis after the delivery, bacterial culture tests were performed on her breast milk, in addition to vaginal and stool culture tests. GBS was exclusively detected in the mother's breast milk. The GBS strains detected in the cerebrospinal fluid of the neonate and the mother's breast milk were both serotype III, and were confirmed to be identical through pulsed-field gel electrophoresis analysis. As horizontal GBS transmission between the mother and neonate was indicated, breastfeeding was ceased and replaced with formula milk. No recurrence of bacterial meningitis or bacteremia due to GBS was observed thereafter. Physicians need to consider culturing breast milk in cases of recurrent neonatal GBS infections, even in mothers without prior detection of GBS in conventional vaginal or stool cultures before delivery.