A comprehensive review of early-onset sepsis: current epidemiology and diagnostic challenges

Recent trends in early-onset sepsis

Clinicians and researchers have observed shifting patterns in early-onset sepsis (EOS) over the past decade. Group B Streptococcus (GBS) remains a leading pathogen, but the proportion of cases caused by Escherichia coli and other Gram-negative organisms has increased, particularly among preterm infants. Concurrently, the widespread adoption of intrapartum antibiotic prophylaxis has reduced GBS incidence, though it has not eliminated EOS entirely. Changes in maternal demographics, such as rising rates of preterm birth and antibiotic exposure, continue to influence pathogen distribution.

Background and diagnostic challenges

Early-onset sepsis—typically defined as a positive blood or cerebrospinal fluid culture within the first 72 hours of life—poses a persistent clinical dilemma. The classic signs are non-specific and can overlap with respiratory distress or metabolic disorders, making timely diagnosis difficult. Key challenges include:

• Low sensitivity of maternal risk-factor-based screening
• Delays in culture results (typically 24–48 hours)
• Limited availability of rapid molecular tests in many settings
• False negatives from intrapartum antibiotics masking bacteremia

These factors often force clinicians to start empirical antibiotics in a large number of asymptomatic or mildly symptomatic newborns, contributing to overtreatment and disruption of the infant microbiome.

User concerns and clinical decision points

For pediatric care teams and neonatal units, the central question is how to balance early treatment of a potentially devastating infection against the harms of unnecessary antibiotic exposure. Concerns frequently raised include:

• Which newborns most urgently need lumbar puncture?
• How should serial clinical assessments modify antibiotic duration?
• What is the optimal role of biomarkers (e.g., CRP, procalcitonin) in serial monitoring?
• When is it safe to discontinue antibiotics after 48 hours with negative cultures and reassuring exam?

Many centers are adopting risk-stratification algorithms that combine perinatal factors with serial physical exams, but no single tool has proven universally superior.

Likely impact on clinical practice

Several ongoing shifts are expected to refine EOS management over the next few years:

• Greater reliance on neonatal sepsis calculators – Tools such as the Kaiser Permanente calculator are being adapted for diverse populations, reducing unnecessary antibiotic initiation without missing true cases.
• Expanded use of molecular diagnostics – Multiplex PCR panels on blood and cerebrospinal fluid can shorten time to pathogen identification, though cost and validation remain barriers.
• Narrower empiric antibiotic spectrums – Evidence is accumulating that ampicillin plus gentamicin remains appropriate in most settings, with broader coverage reserved for high-risk or Gram-negative dominant units.
• Enhanced surveillance systems – Regional networks are tracking pathogen trends to update prophylaxis guidelines, particularly regarding emerging antimicrobial resistance patterns.

What to watch next

Key areas to monitor in the coming years include:

• Updates to CDC/AAP preventive guidelines, especially for late preterm and low-birth-weight infants
• Real-world validation of rapid biomarker panels combined with continuous clinical monitoring
• Impact of maternal COVID-19 and other viral infections on neonatal sepsis epidemiology
• Long-term neurodevelopmental outcomes among infants treated for suspected versus confirmed EOS
• Integration of machine learning algorithms into electronic health records to flag high-risk newborns in near real-time