## Early-Onset Neonatal Sepsis (EONS) — Microbiology **Key Point:** In India and most developing countries, Gram-negative organisms, particularly E. coli, are the leading cause of EONS, whereas GBS predominates in developed nations. ### Geographic Variation in EONS Pathogens | Region | Most Common Organism | Second Most Common | |--------|----------------------|--------------------| | Developed countries (USA, Europe) | GBS (Group B Streptococcus) | E. coli | | India & developing countries | E. coli | Klebsiella pneumoniae | | Overall neonatal sepsis (EONS + LONS) | E. coli | GBS | ### Why E. coli Dominates in India 1. **Maternal colonization**: Gram-negative organisms (especially E. coli) are more prevalent in maternal genital flora in developing countries. 2. **Vertical transmission**: Ascending infection during labor and delivery is the primary route of EONS. 3. **Lower GBS colonization rates**: GBS colonization is less common in Indian pregnant women compared to Caucasian populations. **High-Yield:** EONS occurs within the first 72 hours of life; the organism is acquired from maternal genital flora during delivery or ascending infection in utero. **Clinical Pearl:** Ampicillin + Gentamicin (or Ceftazidime) is the empiric regimen for EONS in India, covering both GBS (if present) and Gram-negative organisms including E. coli and Klebsiella. **Warning:** Do not assume GBS is the most common cause in all populations — this is a common trap for students trained on Western textbooks. Always contextualize to the Indian setting.
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.