Which clinical feature best distinguishes early-onset neonatal sepsis (EONS) from late-onset neonatal sepsis (LONS) in a 2-week-old neonate presenting with fever and poor feeding?

Explanation

## Distinguishing Early-Onset vs Late-Onset Neonatal Sepsis **Key Point:** The timing of presentation is the fundamental criterion that separates EONS from LONS, with EONS occurring within the first 72 hours of life and LONS after 72 hours. ### Comparison Table | Feature | Early-Onset Sepsis (EONS) | Late-Onset Sepsis (LONS) | | --- | --- | --- | | **Age of onset** | < 72 hours (typically < 24 hrs) | ≥ 72 hours to 28 days | | **Primary source** | Vertical transmission (maternal) | Horizontal transmission (environment/healthcare) | | **Common organisms** | GBS, *E. coli* K1, *Listeria* | *Staphylococcus epidermidis*, *Staph. aureus*, Gram-negatives, Candida | | **Risk factors** | Maternal chorioamnionitis, prolonged rupture of membranes, maternal fever, GBS colonization | Invasive procedures, prolonged hospitalization, central lines | | **Clinical presentation** | Fulminant, respiratory distress, shock | Variable, often indolent | **High-Yield:** The age cutoff of 72 hours is the single most important discriminator and is universally used in clinical practice and guidelines. **Clinical Pearl:** A neonate presenting at 48 hours with sepsis is EONS until proven otherwise, whereas one presenting at 5 days is LONS. This distinction drives empiric antibiotic choice — EONS requires ampicillin + gentamicin (or cefotaxime) to cover GBS and *Listeria*, while LONS empiric therapy is typically broader to include hospital-acquired pathogens. **Mnemonic:** **EONS = Early (< 72 hrs), Obstetric origin (vertical transmission)** [cite:Nelson Textbook of Pediatrics 21e Ch 102]