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

The Most Common Source of Infection in Burn Patients

The burn wound itself is the most common source of infection in burn patients (a). 1 Damage to the skin barrier following a burn disrupts the innate immune system and increases susceptibility to bacterial infection, making the burn wound the primary site for infectious complications.

Pathophysiology of Burn Wound Infections

• Burn wounds are initially sterile immediately following thermal injury but become rapidly colonized by microorganisms 1
• The colonization pattern typically follows a predictable sequence:
  • Initial colonization by Gram-positive bacteria from the patient's endogenous skin flora
  • Rapid colonization by Gram-negative bacteria, usually within a week of the burn injury 1
• Burn wound infections are typically polymicrobial in nature 1, 2

Epidemiology and Impact

• Infections are the most common complication and cause of death in patients with burn injuries 3
• In a series of 175 patients with severe burns, infections preceded multiorgan dysfunction in 83% of patients and were directly responsible for 36% of deaths 1
• The risk of infection increases significantly with burn size, particularly when total body surface area (TBSA) exceeds 40% 4

Other Sources of Infection in Burn Patients

While the burn wound is the primary source, other infection sites include:

1. Pneumonia - The second most common infection in burn patients and now the most frequent infection in modern burn care due to improvements in wound management 5
2. Urinary tract infections - Often associated with indwelling catheters
3. Bloodstream infections - Usually secondary to wound infection 3
4. Thrombophlebitis - Less common but can occur with indwelling vascular devices
5. Endocarditis - Rare complication

Microbiology of Burn Wound Infections

• Early colonization: Predominantly Gram-positive organisms (Staphylococcus aureus)
• Later colonization: Predominantly Gram-negative organisms (Pseudomonas aeruginosa, Acinetobacter spp.) 2, 5
• Emerging resistant pathogens:
  • Multidrug-resistant Staphylococcus aureus (MRSA)
  • Pseudomonas aeruginosa
  • Acinetobacter species
  • Various fungal strains (Candida spp., Aspergillus spp., and Fusarium spp.) 2, 6

Diagnosis of Burn Wound Infections

• Surface swabs reflect only surface colonization rather than deep tissue invasion 1
• Quantitative bacterial cultures of tissue biopsies are recommended to accurately assess infection 1
• Histopathological examination of biopsied tissue helps determine the extent of microbial invasion 1
• Prior to sampling, wounds should be thoroughly cleansed and free of topical antimicrobials that can affect culture results 1

Prevention and Management

• Early excision of necrotic tissue (eschar) substantially decreases the incidence of invasive burn wound infection 1, 4
• Topical antimicrobial agents help control surface bacterial proliferation
• Systemic antibiotic prophylaxis in the first 4-14 days has been shown to reduce all-cause mortality by nearly half 1
• Regular wound surveillance and biopsy monitoring are necessary to assess the microbial status of burn wounds 5
• Strict infection control measures, including isolation protocols, are essential to prevent cross-contamination 2, 6

Key Takeaways

• The burn wound remains the primary source of infection in burn patients due to the disruption of the skin barrier and subsequent immunosuppression
• Early recognition and aggressive management of burn wound infections are crucial to improving outcomes
• Advances in wound care, surgical techniques, and antimicrobial therapies have significantly reduced morbidity and mortality from burn infections, but they remain a major challenge in burn management