Neonatal Sepsis: Risk Factors, Recognition, and Management

Neonatal sepsis is a life-threatening systemic infection in the first 28 days of life and a leading cause of newborn morbidity and mortality. This note reviews how to distinguish early- from late-onset disease, recognize subtle clinical signs, and act quickly with cultures, empiric antibiotics, and supportive care.

Definition

• Neonatal sepsis: systemic infection occurring in the first 28 days of life.
• Early-onset sepsis (EOS): within 72 hours of birth; usually acquired from the mother (vertical transmission).
• Late-onset sepsis (LOS): after 72 hours; usually acquired from the environment (horizontal transmission).

Risk Factors

Maternal

• Chorioamnionitis (infection of amniotic fluid and fetal membranes) — a major risk factor for EOS
• Prolonged rupture of membranes (>18 hours) — increases risk of ascending infection
• Maternal fever
• Group B Streptococcus (GBS) colonization

Fetal/neonatal

• Prematurity — immature immune system increases susceptibility
• Low birth weight
• Low Apgar scores
• Male sex

Intrapartum

• Premature rupture of membranes
• Prolonged labor
• Fetal distress

Signs and Symptoms

• Temperature instability — fever or hypothermia (hypothermia is more common in preterm infants)
• Respiratory distress — tachypnea, grunting, retractions, apnea
• Feeding intolerance — poor feeding, vomiting, abdominal distension
• Lethargy — decreased responsiveness
• Hypotension and bradycardia — late signs of cardiovascular compromise
• Jitteriness or seizures — from metabolic disturbances or meningitis
• Pallor or mottling — indicates poor perfusion

Early-Onset vs Late-Onset Sepsis

• EOS often presents with respiratory distress in the first 24–48 hours.
• LOS often presents with subtle signs such as poor feeding and lethargy.

Diagnosis

• Blood culture — gold standard; obtain before starting antibiotics
• CSF analysis — when meningitis is suspected
• CBC — leukopenia or leukocytosis; left shift suggests infection
• CRP and procalcitonin — markers of bacterial infection

Treatment

• Start empiric antibiotics immediately:
  • Ampicillin — covers GBS and Listeria
  • Gentamicin or cefotaxime — covers gram-negative organisms
• Adjust antibiotics based on culture and sensitivity results.
• Supportive care: oxygen, IV fluids, and respiratory support as needed.

Prevention

• Maternal GBS screening at 35–37 weeks gestation.
• Intrapartum antibiotic prophylaxis for GBS-positive women — penicillin or ampicillin.
• Hand hygiene — the single most important measure for preventing late-onset sepsis.
• Breastfeeding provides passive immunity and reduces sepsis risk.

Exam Traps

• Do not ignore subtle signs — poor feeding and lethargy may be the earliest clues.
• Do not delay antibiotics; sepsis is a medical emergency.
• A normal temperature does not rule out sepsis — instability includes both fever and hypothermia.
• Always obtain blood cultures before giving antibiotics.
• Full-term infants are also at risk — do not dismiss them.
• Remember GBS is the most common cause of early-onset sepsis.
• Do not ignore apnea in a septic infant.
• Late-onset sepsis can present with meningitis.

Key takeaways

• Neonatal sepsis is early-onset (≤72 h, maternal source) or late-onset (>72 h, environmental source).
• GBS is the leading cause of EOS; screen mothers at 35–37 weeks and give intrapartum penicillin/ampicillin if positive.
• Suspect sepsis with temperature instability, respiratory distress, poor feeding, lethargy, or apnea — signs are often subtle.
• Obtain blood cultures first, then start empiric ampicillin + gentamicin (or cefotaxime) without delay.
• Hand hygiene is the most important intervention to prevent late-onset sepsis; breastfeeding adds passive immunity.