What is the recommended treatment for a Methicillin-resistant Staphylococcus aureus (MRSA) positive throat swab?

Treatment of MRSA Positive Throat Swab

For MRSA positive throat swab, oral rifampicin combined with either clindamycin or trimethoprim-sulfamethoxazole (TMP-SMX) for 7 days, plus nasal mupirocin, is recommended as the most effective eradication therapy. 1

First-line Treatment Options

Systemic Therapy (Preferred)

• Combination therapy:
  • Rifampicin 600 mg orally once daily (or 300-450 mg twice daily) PLUS one of the following:
    • Clindamycin 300-450 mg orally three times daily OR
    • TMP-SMX (1-2 double-strength tablets) orally twice daily
  • Duration: 7 days
  • Add nasal mupirocin ointment twice daily for 5-10 days

This combination approach has shown significantly better eradication rates (61% at 6 months) compared to topical treatment alone (12%) 1.

Alternative Options

If the patient cannot tolerate the first-line regimen, consider:

1. Linezolid 600 mg orally twice daily for 7-10 days (A-II) 2

   • Highly effective against MRSA
   • Expensive but has excellent oral bioavailability
   • Monitor for myelosuppression with prolonged use

2. Doxycycline or Minocycline 100 mg orally twice daily for 7-10 days (A-II) 2

   • Contraindicated in pregnancy and children under 8 years
   • Lower cost option

3. Clindamycin monotherapy 300-450 mg orally three times daily for 7-10 days (A-II) 2

   • Check for inducible resistance before using as monotherapy
   • Higher risk of C. difficile infection

Special Considerations

For Severe Infections or Systemic Involvement

If the throat carriage is associated with signs of invasive infection:

• Vancomycin 15-20 mg/kg IV every 8-12h (target trough 15-20 μg/mL) 2
• Consider adding rifampicin 600 mg daily once bacteremia is cleared 2

Pediatric Patients

• Clindamycin 10-13 mg/kg/dose orally every 6-8 hours (not to exceed 40 mg/kg/day) (A-II) 2
• Linezolid for children >12 years: 600 mg twice daily; for children <12 years: 10 mg/kg every 8 hours (A-II) 2

Adjunctive Measures

• Chlorhexidine body wash for 5-14 days 2
• Consider dilute bleach baths for extensive colonization 2
• Ensure proper hygiene and environmental cleaning

Monitoring and Follow-up

• Repeat throat cultures at 2 weeks, 2 months, and 6 months after treatment 1
• If persistent carriage is detected, consider alternative regimen or infectious disease consultation

Important Caveats

• Do not use rifampicin as monotherapy due to rapid development of resistance (A-III) 2, 3
• Check for drug interactions with rifampicin as it induces cytochrome P450 enzymes
• For patients with penicillin allergy, avoid beta-lactams and use alternative agents listed above
• Consider local resistance patterns when selecting therapy

The evidence strongly supports combination therapy over monotherapy for MRSA throat carriage, with rifampicin-based regimens showing the best eradication rates. Treatment should be accompanied by appropriate decolonization measures to prevent recurrence and transmission.