Most Common Source of Infection in Burn Patients
The burn wound is the most common source of infection in burn patients (option a). Damage to the skin barrier following a burn disrupts the innate immune system and increases susceptibility to bacterial infection, making the burn wound itself the primary site for infectious complications 1.
Pathophysiology and Microbiology of Burn Wound Infections
- Burn wounds are initially sterile immediately following thermal injury but become rapidly colonized with microorganisms 1
- The colonization pattern typically follows a predictable sequence:
- Initial colonization by Gram-positive bacteria from the patient's endogenous skin flora or external environment
- 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
- Common pathogens include:
- Gram-positive: Staphylococcus aureus (including MRSA)
- Gram-negative: Pseudomonas aeruginosa, Acinetobacter species
- Fungal pathogens: Candida species, Aspergillus, and Fusarium 2
Evidence Supporting Burn Wound as Primary Source
- In severe burn patients, infections preceded multiorgan dysfunction in 83% of patients and were considered the direct cause of death in 36% of patients 1
- Most cases of sepsis in burn patients originate from infected burn wounds 3
- While pneumonia is common in burn patients, it is not the primary source of infection 4
- The burn wound itself serves as the portal of entry for systemic infections, including bacteremia 4
Diagnostic Approaches
- Surface swabs or tissue biopsies are recommended for monitoring burn wound infections 1
- Quantitative culture is preferred, with optimal utilization requiring twice weekly sampling of the same site to accurately monitor bacterial colonization trends 1
- Tissue biopsy is superior to surface swabs as it reflects the microbial invasion at the advancing margin rather than just surface colonization 1
- Histopathological examination of tissue biopsies provides additional information about the extent of microbial invasion 1
Prevention and Management
- Early excision of necrotic tissue (eschar) can substantially decrease the incidence of invasive burn wound infection 1, 3
- Topical antimicrobial agents are commonly used but have shown variable efficacy 1
- Systemic antibiotic prophylaxis in the first 4-14 days has been shown to reduce all-cause mortality by nearly half 1
- Strict infection control measures, including patient isolation and staff hygiene protocols, are essential to prevent cross-contamination 4, 5
Other Sources of Infection in Burn Patients
While the burn wound is the primary source, other important sources of infection in burn patients include:
- Pneumonia (second most common) - particularly in patients with inhalation injuries or those requiring mechanical ventilation 6, 4
- Urinary tract infections - associated with indwelling catheters 3
- Catheter-related bloodstream infections - due to necessary vascular access 2
- Thrombophlebitis - less common than the above sources 2, 6
Risk Factors for Infection
- Total body surface area burned (TBSA) - risk increases significantly with burns >40% TBSA 3
- Depth of burn injury 3
- Presence of inhalation injury 3
- Indwelling devices 3
- Delays in burn wound excision 6
The evidence clearly demonstrates that the burn wound itself is the most common source of infection in burn patients, followed by pneumonia, urinary tract infections, and catheter-related bloodstream infections.