Sepsis, Neonatal



  • Clinical syndrome characterized by systemic infection occurring within the first 28 days of life
  • Early-onset sepsis (EOS) and late-onset sepsis (LOS) occur within and following the first 72 hours of life, respectively.
  • Some consider infection within the first 7 days of life early onset, especially in term infants who are not hospitalized.


  • EOS: 1/1,000 live births in the United States. Incidence is much higher among very-low-birth-weight (VLBW) neonates.
  • LOS: Among febrile neonates presenting to the emergency department, approximately 12% are diagnosed with a serious bacterial infection. Incidence among hospitalized preterm infants is inversely associated with birth weight.

Risk Factors

  • Neonates are at increased risk for infection due to their immature immune system (permitting relative immune tolerance) and their developing, under-keratinized cutaneous barrier.
  • Maternal factors:
    • Low socioeconomic status
    • Illicit substance use
    • Inadequate or no prenatal care
    • Poor maternal nutrition
    • Intra-amniotic procedures
    • Preterm labor, prolonged or premature rupture of membranes
    • Chorioamnionitis or “intrauterine inflammation, infection, or both” (III, “triple I”; a new term describing the heterogenous conditions labeled previously as chorioamnionitis)
    • Presence of cervical cerclage
    • Septic/traumatic delivery
    • Peripartum infection, including urinary tract infections (UTIs)
    • Group B Streptococcus (GBS) colonization
    • Ingestion of contaminated foods during pregnancy (Listeria)
  • Infant factors:
    • Male sex
    • Prematurity or low birth weight
    • Low Apgar scores
    • Congenital anomalies
    • Compromised skin integrity
    • Galactosemia (Escherichia coli sepsis)
    • Invasive procedures,
    • Presence of central line


Single nucleotide polymorphisms (SNPs) in genes involved in inflammation have been linked to increased risk of neonatal sepsis.

General Prevention

  • Recognition and treatment of maternal peripartum infections and colonization (i.e., GBS)
  • General obstetric practices to reduce risk of chorioamnionitis/III and postnatal clean cord care
  • Thermoregulation and early breastfeeding
  • Hand hygiene, avoidance of fomites


  • EOS: primarily vertical transmission, with ante- or intrapartum acquisition of bacteria colonizing the maternal genitourinary tract
  • LOS: primarily due to horizontal transmission or nosocomial infection in hospitalized infants


  • EOS:
    • GBS is most common (~40%), followed by E. coli (~20–30%), other streptococci (~10%).
    • Incidence of GBS disease has decreased since initiation of intrapartum antibiotic prophylaxis (IAP).
    • E. coli is the most common pathogen in VLBW infants.
    • Overall incidence of Listeria sepsis is low, but it is more common in preterm infants.
    • Viral pathogens, including enteroviruses, may present with EOS.
  • LOS:
    • GBS and E. coli remain important; consider Staphylococcus aureus (up to a quarter methicillin-resistant) and coagulase-negative staphylococci (CoNS), especially in hospitalized infants.
    • Pseudomonas aeruginosa carries the highest mortality risk in preterm infants (up to 75%).
    • Yeast infections should be considered, with hospitalized preterm infants at greatest risk.
    • Viral pathogens, including enteroviruses, may present with LOS; viral meningitis is more common in the late-onset period.
    • Perinatally acquired HSV infection should be considered in neonates at any period during the 1st month of age.

Commonly Associated Conditions

  • Meningitis: Up to a quarter of neonates with bacteremia have meningitis.
  • Pneumonia
  • UTI
  • Omphalitis
  • Osteomyelitis
  • Severe hyperbilirubinemia
  • Persistent pulmonary hypertension of the newborn (PPHN)
  • Patent ductus arteriosus (PDA)

There's more to see -- the rest of this topic is available only to subscribers.