Neonatal sepsis and meningitis caused by Group B Streptococcus or Escherichia coli in twins. A systematic review

Neonatal sepsis in one twin poses a dilemma in managing the healthy-appearing sibling. Shared exposures and genetic factors increase risk, and early signs of sepsis can be subtle with rapid deterioration. However, the magnitude of this risk for the healthy twin is unclear, and management strategies vary considerably.

We systematically searched PubMed and EMBASE on June 10th 2025 for multiples in which at least one infant (0-89 days) developed culture-confirmed Group B Streptococcus or Escherichia coli early-onset or late-onset sepsis or meningitis.

Of 151 sets of multiples from 51 studies, all siblings developed disease in 70 sets (46%). Concordance was 35% in cases described in cohort or surveillance studies and 69% among cases in case reports/series. Median onset interval between siblings was 3 days (IQR 1-7 days). In a small subgroup, pre-emptive antibiotics for the well-appearing twin were associated with lower disease risk (11% vs 56%, p=0.03).

Concordance rates of the well-appearing sibling was a third in cohort or surveillance studies and up to half in all identified cases. Even though this can be inflated by reporting bias, cautious management should include strict clinical monitoring, parental education and a low threshold for antibiotics.