What is the recommended duration of antibiotic therapy for severe burns?

Duration of Antibiotic Therapy for Severe Burns

For severe burns, systemic antibiotics should NOT be used routinely as prophylaxis, and when infection is confirmed, treatment duration should be limited to no more than 24 hours after adequate source control in the absence of clinical signs of active infection. 1

Key Principle: Antibiotics Are Not First-Line Treatment

The cornerstone of burn infection prevention is early surgical excision of necrotic tissue and eschar, not prophylactic antibiotics. 2 The evidence consistently shows that routine systemic antibiotic prophylaxis should be avoided in burn patients due to:

• No proven benefit: Multiple randomized trials show no reduction in infection rates with routine prophylaxis 3, 4
• Significant harm: Increased risk of multidrug-resistant bacteria, including a 2.22-fold increase in MRSA rates when non-absorbable antibiotics plus cefotaxime were used 1
• Low quality evidence: Only three small randomized trials exist with mixed results 4

When to Use Antibiotics in Severe Burns

Prophylactic Use (Limited Indications)

Systemic antibiotic prophylaxis administered in the first 4-14 days significantly reduced all-cause mortality by nearly half in one meta-analysis, though this conflicts with current guidelines that recommend against routine use. 1, 4 The specific scenarios where prophylaxis may be considered include:

• Mechanically ventilated burn patients: One small study (40 participants) showed trimethoprim-sulfamethoxazole reduced pneumonia risk (RR = 0.18; 95% CI: 0.05 to 0.72) 1
• Perioperative prophylaxis for skin grafting: Limited to the surgical procedure itself 3, 4

Treatment of Confirmed Infection

When infection is documented, antibiotics should be:

• Culture-directed: Selection based on bacterial cultures, not empirical 3
• Time-limited: No more than 24 hours after adequate source control if no active infection signs persist 1
• Broad-spectrum initially: Cover both Gram-positive and Gram-negative facultative organisms plus anaerobes 2

Specific Antibiotic Recommendations for Confirmed Infections

For Staphylococcus aureus (including MRSA)

• Oral options: Dicloxacillin, cefalexin, clindamycin, doxycycline, or sulfamethoxazole-trimethoprim 3
• For MRSA specifically: Clindamycin, doxycycline, or sulfamethoxazole-trimethoprim 3
• Intravenous reserve agents: Vancomycin and linzolid (100% and 83% effective respectively against MRSA in burn patients) 5, 6

For Gram-Negative Organisms (Pseudomonas, Acinetobacter)

• Most effective agents: Imipenem, amikacin, and colistin 5, 6
• Important caveat: Standard dosing of piperacillin/tazobactam (4/0.5g tid) results in subtherapeutic levels in burn patients—consider 8/1g qid with 3-hour infusion 7
• Colistin: Re-emerged as highly effective against multidrug-resistant Pseudomonas and Acinetobacter 5

Critical Pitfalls to Avoid

Dosing Errors

Standard antibiotic doses are often inadequate in burn patients due to altered pharmacokinetics from hypermetabolic state and augmented renal clearance. 8, 7 Therapeutic drug monitoring should be performed when available to optimize dosing. 8

Topical Antibiotic Misuse

• Silver sulfadiazine: Prolonged use on superficial burns delays healing and increases length of hospital stay (MD = 2.11 days; 95% CI: 1.93 to 2.28) compared to dressings/skin substitutes 1, 3
• Topical antibiotics should be reserved for infected wounds only, not used as first-line prophylaxis 3, 2

Failure to Distinguish Colonization from Infection

Burn wounds become colonized within days but this does not equal infection. 2, 4 Obtain bacterial cultures when infection is suspected to guide appropriate therapy rather than treating colonization. 3

Monitoring Requirements

• Daily wound assessment: Dressings should be evaluated daily for signs of infection 3, 2
• Culture surveillance: Obtain cultures at 72 hours post-admission and whenever fever develops 6
• Source control verification: Ensure adequate debridement and removal of necrotic tissue, which is more important than antibiotic duration 1, 4

Special Populations

Diabetic Patients with Infected Burns

For mild infections, use: Dicloxacillin, clindamycin, cefalexin, levofloxacin, amoxicillin-clavulanic acid, or doxycycline. 3

Contaminated Wounds (Animal/Human Bites)

Amoxicillin-clavulanic acid is the preferred oral option. 3