 In this observational study, the NICHD Neonatal Research Network NRN is conducting surveillance of all infants born at NRN centers to identify all newborns who are diagnosed with early-onset sepsis EOS andor meningitis. The study will: establish current hospital-based rates of EOS among term and preterm infants in the era of intrapartum antibiotic prophylaxis; monitor the organisms associated with EOS and meningitis; compare asymptomatic and symptomatic infants by gestational age and pathogen; and monitor sepsis-associated mortality rates by pathogen group. 