What is the treatment for Methicillin-resistant Staphylococcus aureus (MRSA) infection in a wound?

Treatment of MRSA in Wounds

For MRSA wound infections, the primary treatment is incision and drainage of abscesses, followed by appropriate antibiotic therapy based on wound severity, with options including clindamycin, trimethoprim-sulfamethoxazole, tetracyclines, or linezolid for outpatients, and vancomycin, linezolid, daptomycin, or telavancin for hospitalized patients. 1

Initial Management

• Incision and drainage is the primary treatment for cutaneous abscesses caused by MRSA 1
• For simple abscesses or boils, incision and drainage alone may be adequate without antibiotic therapy 1
• Cultures from abscesses and purulent wounds should be obtained, especially in patients requiring antibiotic therapy, those with severe infections, or when there is concern for treatment failure 1

Antibiotic Selection Based on Wound Severity

Mild to Moderate Outpatient Infections

For outpatients with MRSA wound infections requiring antibiotics (due to extensive disease, rapid progression, systemic symptoms, or immunosuppression):

• Oral antibiotic options include:

  • Clindamycin 300-450 mg three times daily (A-II) 1, 2
  • Trimethoprim-sulfamethoxazole (TMP-SMX) 1-2 double-strength tablets twice daily (A-II) 1, 2
  • Doxycycline or minocycline 100 mg twice daily (A-II) 1
  • Linezolid 600 mg twice daily (A-II) 1, 3

• Duration of therapy: 5-10 days, adjusted based on clinical response 1

Severe or Complicated Infections (Hospitalized Patients)

For complicated wound infections (deeper soft-tissue infections, surgical/traumatic wound infections, major abscesses):

• Intravenous antibiotic options include:

  • Vancomycin IV (A-I) 1
  • Linezolid 600 mg IV/PO twice daily (A-I) 1, 3
  • Daptomycin 4 mg/kg IV once daily (A-I) 1, 4
  • Telavancin 10 mg/kg IV once daily (A-I) 1
  • Clindamycin 600 mg IV three times daily (A-III) 1

• Duration of therapy: 7-14 days, individualized based on clinical response 1

Special Considerations

• Surgical debridement is essential for complicated infections and should be performed whenever feasible 1
• Rifampin should not be used as a single agent or as adjunctive therapy for MRSA skin infections (A-III) 1, 2
• For wounds with both MRSA and Pseudomonas, combination therapy targeting both pathogens may be necessary 2
• Daptomycin has shown non-inferiority to vancomycin in treating MRSA bacteremia and may be considered for more severe infections 5
• Newer agents like ceftaroline, tedizolid, dalbavancin, and oritavancin are available for MRSA skin infections but have less extensive clinical experience 6, 7

Pediatric Considerations

• For children with MRSA wound infections:
  • Mupirocin 2% topical ointment can be used for minor skin infections (A-III) 1
  • Tetracyclines should not be used in children under 8 years of age (A-II) 1
  • For more severe infections, IV vancomycin is recommended (A-II) 1
  • Clindamycin (10-13 mg/kg/dose IV every 6-8 hours) is an option if local resistance rates are low (<10%) 1
  • Linezolid dosing: 600 mg twice daily for children >12 years; 10 mg/kg every 8 hours for children <12 years 1

Monitoring and Follow-up

• Monitor for clinical improvement within 48-72 hours of appropriate therapy 2
• If no improvement occurs, reassess for:
  • Need for additional surgical debridement
  • Development of abscess
  • Possibility of osteomyelitis
  • Need for antibiotic adjustment based on culture results 2
• For recurrent infections, implement preventive measures including wound coverage, personal hygiene, and environmental cleaning 2

Pitfalls and Caveats

• Vancomycin remains effective but has limitations including poor tissue penetration and slow bacterial killing 5, 8
• Resistance can emerge during quinolone monotherapy; if used, quinolones should be combined with another active agent like rifampin 9
• Beta-lactam antibiotics (e.g., cefazolin) are ineffective against MRSA by definition, despite in vitro synergy observed in some studies 8
• Combination antibiotic therapy for MRSA has shown conflicting results in studies and is not routinely recommended outside of clinical trials 8