What are the causes of omphalitis?

Causes of Omphalitis

Omphalitis results from bacterial colonization of the devitalized umbilical cord, with Staphylococcus aureus being the most frequently reported pathogen, followed by Group A and B Streptococci and Gram-negative bacilli including E. coli, Klebsiella, and Pseudomonas species. 1

Primary Bacterial Pathogens

The umbilical cord becomes infected through specific bacterial sources:

• Staphylococcus aureus is the predominant organism isolated in omphalitis cases across all studies, with methicillin-susceptible strains (MSSA) accounting for 95.7% and methicillin-resistant strains (MRSA) for 4.2% 2
• Group A Streptococcus (Streptococcus pyogenes) represents approximately 18% of isolates 2
• Group B Streptococcus accounts for approximately 10% of cases 2
• Gram-negative bacilli including Escherichia coli, Klebsiella species, and Pseudomonas species are common secondary pathogens 1, 3
• Anaerobic and polymicrobial infections occur rarely but should be considered in severe cases 1

Sources of Bacterial Contamination

The devitalized umbilical cord provides an ideal medium for bacterial growth, with contamination occurring from specific sources:

• Maternal birth canal serves as the primary source of bacterial exposure during delivery 1, 4
• Nonsterile hands of any person assisting with delivery represent the most prominent local bacterial source 1, 4
• Environmental contamination at the delivery site, particularly in home births 1

Risk Factors That Predispose to Omphalitis

Certain clinical circumstances dramatically increase the risk of developing umbilical infection:

• Unplanned home birth or septic delivery increases risk 6-fold compared to hospital births in resource-limited settings 1
• Low birth weight (less than 2500 grams) significantly increases susceptibility 1, 3
• Prolonged rupture of membranes allows ascending bacterial colonization 1
• Umbilical catheterization creates a direct portal for bacterial entry 1
• Chorioamnionitis indicates pre-existing maternal-fetal infection 1

Age-Specific Causes in Adults

While omphalitis primarily affects neonates, adults develop umbilical infections through different mechanisms:

• Navel piercing is the most common cause in adults, with bacterial contamination during or after the piercing procedure 5
• Frictional irritation from jewelry and migration/rejection of jewelry create portals for infection 5
• The same bacterial pathogens (S. aureus, Streptococci, Gram-negative bacilli) cause adult umbilical infections 5

Critical Clinical Pitfall

Even painless whitish discharge from the umbilicus may represent early infection with potential for serious complications due to direct vascular access to the bloodstream. 4 The umbilical vessels provide a direct route for bacterial invasion, leading to potentially catastrophic complications including sepsis, portal vein thrombophlebitis, peritonitis, necrotizing fasciitis, and intra-abdominal abscess formation, with case-fatality rates as high as 13% in untreated cases 4, 6, 7.