This prospective surveillance study will be conducted over a 2 year period to determine current rates of Early-Onset Sepsis (EOS)/ Early-Onset Meningitis (EOM), associated pathogens, antimicrobial resistance, signs and symptoms and infant outcomes.

Neonatal pathogens other than group B Streptococcus (GBS) and resistant to beta-lactam antibiotics have emerged as the most common etiologic agents of EOS and EOM among preterm and term neonates and result in high mortality rates, potentially offsetting the decreased burden of early-onset GBS disease prevented by maternal intrapartum chemoprophylaxis.

Primary Outcomes of this study:

1. To determine current hospital-based rates of early-onset neonatal infection (total, GA-specific and BW-specific, and pathogen-specific) in term and preterm infants in the era of maternal intrapartum antibiotic prophylaxis to prevent vertical transmission of group B streptococcal disease. Early-onset infection comprises EOS and/or EOM and is defined as isolation of a pathogen from blood or cerebrospinal fluid (CSF) obtained within 72 hours of birth and provision of appropriate antibiotic treatment for 5 or more days (or <5 days if death occurs while receiving antibiotic therapy).
2. To determine the antimicrobial susceptibility patterns of organisms associated with EOS and EOM

The case control aspect of this study will address 2 major conundrums regarding EOS: Can we identify risk factors for early-onset Gram-negative infections that might lead to intervention strategies to reduce risk and can we identify infants born to mothers with clinical chorioamnionitis who are at highest risk for early-onset sepsis and thus warrant antibiotic treatment soon after birth?

Inclusion Criteria:

• Case Surveillance: Live born infants with gestational age of at least 22 weeks and birth weight >400 g and <72 hours of age who are delivered at NRN hospitals and have early-onset sepsis and meningitis defined as isolation of a pathogen from blood or CSF obtained within 72 hours of birth and provision of appropriate antibiotic treatment for 5 or more days (or <5 days if death occurs while receiving antibiotic therapy).
• Controls: Live born infants with gestational age of at least 22 weeks and birth weight >400 g who are delivered at NRN hospitals and have not been evaluated for early-onset sepsis (<72 hours of age) or if evaluated, they have sterile blood and/or CSF cultures and were not treated with prolonged antibiotics for clinical "culture negative" sepsis. Controls for infants with Gram-negative infection will be infants without early-onset infection. Controls for infants born to mothers with clinical chorioamnionitis will be infants without early-onset infection born to mothers with clinical chorioamnionitis. Control infants will be born at the same hospital as cases, with the same gestational age grouping as cases (22 0/7 - 28 6/7 weeks; 29 0/7 - 33 6/7 weeks; 34 0/7 - 36 6/7 weeks; and ≥ 37 weeks).

Exclusion Criteria:

• Stillbirths and infants who die in the delivery room will be excluded.
• Infants who die within 12 hours of age will be excluded if they have not been evaluated for possible infection-ie, do not have a blood culture obtained to identify EOS.

The study population will include all live born infants who are at least 22 weeks GA and have a birth weight >400 grams and are delivered at NRN centers.