Early-onset neonatal sepsis in the Paris area: a population-based surveillance study from 2019 to 2021.

Background: Early-onset neonatal sepsis (EOS) is a rare condition but an important cause of severe morbidity and mortality in neonates.

Methods: This is a prospective observational study in neonates born at ≥34 weeks of gestation (WG). The primary endpoint was EOS, defined by isolation of pathogenic species from blood culture and/or cerebrospinal fluid culture within 72 hours after birth. Data on EOS were collected exhaustively from all maternity wards in Paris area (April 2019-March 2021).

Results: 108 EOS were recorded (annual incidence, 0.32 per 1000 live births; 95% CI 0.26 to 0.38). In term infants, the most frequent pathogens were group B (GBS) (n=47) and (n=20); in late preterm infants, the most frequent pathogens were (n=15) and GBS (n=7). Fifteen meningitis cases were diagnosed. Five strains (14%) were resistant to both amoxicillin and gentamicin, which is an empiric treatment for EOS. Of the 54 infants with GBS infections, 35 were born from mothers with negative GBS prepartum screening test and 8 from mothers with no screening. Two deaths were reported, both in term infants ( and ).

Conclusion: In neonates ≥34 WG born in the Paris area, GBS was twice as frequent as in term infants. EOS was six times more frequent in late preterm than in term infants and was due to in 60% of cases. Prevention of GBS EOS and empiric antibiotic treatment of EOS could be improved.