Infections and antibiotic therapy in surgical newborn infants

Abstract

Colonisation of the gastro-intestinal tract of newborn infants starts immediately after birth and occurs within a few days. Initially, the type of delivery (passage through the birth canal versus caesarean section) and the type of diet (breast versus formula feeding) might affect the colonisation pattern. Nearly all full-term, formula-fed, vaginally delivered infants were colonised with anaerobic bacteria within 4-6 days. 61% harboured Bacteroides fragilis. In contrast, anaerobes were present in 59% and B. fragilis in only 9% of infants delivered by caesarean section, suggesting that significant contamination occurred during passage through the birth canal. Both prematurity and breast feeding reduced the likelihood of isolating anaerobic species. Enterococci were isolated from all neonates, Escherichia coli from 82.6%, anaerobic cocci from 52.2% and both streptococci and staphylococci from 34.8%. Colonisation of the small bowel occurs perorally. In newborn infants with congenital small bowel obstruction, a faecal-type flora is found immediately proximal to the site of obstruction, and the distal bowel remains sterile.