What is the most common source of infection in burn patients?

Most Common Source of Infection in Burn Patients

The burn wound itself is the most common source of infection in burn patients (option a). 1

Pathophysiology and Epidemiology

Burn wounds create an ideal environment for infection due to:

• Disruption of the skin barrier, which is a critical component of innate immunity
• Presence of necrotic tissue (eschar) that serves as an excellent medium for bacterial growth
• Impaired local blood flow limiting immune cell access
• Systemic immunosuppression following severe burns

The burn wound infection pattern typically follows a progression:

• Initial colonization with gram-positive organisms (primarily from patient's own skin flora)
• Subsequent colonization with gram-negative bacteria, usually within a week of injury 1
• Polymicrobial infections are common in established burn wound infections 1

Infection Sources in Burn Patients (In Order of Frequency)

1. Burn wound - Primary source of infection and sepsis 2, 3
2. Pneumonia - Second most common infection in modern burn care 4
3. Urinary tract infections - Often associated with catheterization
4. Bloodstream infections - Frequently secondary to wound infection
5. Other sources (including thrombophlebitis and endocarditis) - Less common

Diagnostic Approach

Accurate diagnosis of burn wound infection requires:

• Regular wound surveillance and monitoring
• Quantitative tissue cultures (not surface swabs) 1
• Histopathological examination of tissue biopsies to assess microbial invasion 1
• Thorough cleansing of the wound prior to sampling to remove topical antimicrobials that can affect culture results

Common Pathogens

• Early colonization: Gram-positive organisms (Staphylococcus aureus)
• Later colonization: Gram-negative organisms (Pseudomonas aeruginosa, Acinetobacter)
• Emerging concerns: Multi-drug resistant organisms including MRSA, resistant Pseudomonas, and fungal pathogens (Candida, Aspergillus) 5, 6

Management Principles

1. Early excision of necrotic tissue - Removal of eschar significantly decreases invasive burn wound infection risk 1, 3
2. Appropriate topical antimicrobials - Though evidence suggests silver sulfadiazine may increase infection risk compared to modern dressings 1
3. Systemic antibiotics - For established infection, not routine prophylaxis
4. Wound closure - Timely closure reduces infection risk 4
5. Infection control measures - Including patient isolation and strict hygiene protocols

Clinical Pearls and Pitfalls

• Pitfall: Relying solely on clinical signs for diagnosis - these can be unreliable in burn patients 1
• Pitfall: Using surface swabs alone - these reflect surface colonization, not deep tissue infection 1
• Pearl: Quantitative tissue biopsy cultures are essential for accurate diagnosis, especially before grafting 1
• Pearl: Systemic antibiotic prophylaxis in the first 4-14 days may reduce mortality in severe burns, though evidence is mixed 1

While pneumonia has become increasingly common in modern burn care as wound care has improved 4, the burn wound itself remains the primary source of infection and the most significant contributor to morbidity and mortality in burn patients.