Early-onset neonatal sepsis

The baby is hours old. Mother is GBS-positive, the membranes went many hours ago, and she spiked a fever in the second stage. The midwife brings the baby over because "he's a bit gruntier than he was." That sentence, in this infant, is the whole topic. The window between suspecting sepsis and giving the first antibiotic dose is the window that decides outcome — and most of time cultures come back negative and the question becomes one of stewardship, not resuscitation.^[1][2]

Overview and definition

Early-onset neonatal sepsis (EOS) is invasive bacterial infection, usually bacteraemia and sometimes meningitis, acquired from the maternal genital tract around the time of birth and presenting within the first 72 hours of life. The same pathogen spectrum produces late-onset sepsis after that cutoff, but the two syndromes have different organisms, different risk factors, and different management reflexes — keep them separate in your head.^[1][2]

Modern guidance has moved from the word "sepsis" toward "early-onset bacterial infection" for a reason. Most infants treated empirically never grow an organism; they are suspected, not proven. The clinical skill is not the diagnosis of a positive culture — it is the bedside judgement of which infant to treat, for how long, and when to stop. That judgement is the centre of gravity of every EOS question.^[1][3]

^{[1] [3] [4]}

References14ShowHide

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2. [2]Flannery DD, Puopolo KM Neonatal Early-Onset Sepsis Pediatr Clin North Am, 2022.PMID 36316253
3. [3]Puopolo KM, Benitz WE, Zaoutis TE Management of Neonates Born at ≥35 0/7 Weeks' Gestation With Suspected or Proven Early-Onset Bacterial Sepsis Pediatrics, 2018.PMID 30455342
4. [4]Puopolo KM, Benitz WE, Zaoutis TE Management of Neonates Born at ≤34 6/7 Weeks' Gestation With Suspected or Proven Early-Onset Bacterial Sepsis Pediatrics, 2018.PMID 30455344
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11. [11]Weiss SL, Peters MJ, Alhazzani W, et al. Surviving Sepsis Campaign International Guidelines for the Management of Septic Shock and Sepsis-Associated Organ Dysfunction in Children Intensive Care Med, 2020.PMID 32032273
12. [12]Shane AL, Hansen NI, Stoll BJ, et al. Methicillin-resistant and susceptible Staphylococcus aureus bacteremia and meningitis in preterm infants Pediatrics, 2012.PMID 22412036
13. [13]Mukhopadhyay S, Puopolo KM Risk assessment in neonatal early onset sepsis Semin Perinatol, 2012.PMID 23177799
14. [14]GBD 2021 Global Sepsis Collaborators Global, regional, and national sepsis incidence and mortality, 1990-2021: a systematic analysis Lancet, 2025.PMID 41135560