Can Mupirocin Be Used for MRSA?
Yes, mupirocin is highly effective against MRSA and is specifically indicated for both treatment of MRSA skin infections and decolonization of MRSA nasal carriage. 1, 2
FDA-Approved Activity Against MRSA
Mupirocin demonstrates excellent antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) through its unique mechanism of inhibiting bacterial protein synthesis by binding to bacterial isoleucyl transfer-RNA synthetase. 2 This distinct mode of action means mupirocin shows no cross-resistance with other antimicrobial classes. 2
Clinical Applications for MRSA
Topical Treatment of MRSA Skin Infections
- Mupirocin 2% ointment is recommended for localized MRSA skin infections including impetigo and secondarily infected skin lesions (infected eczema, ulcers, lacerations). 1
- Apply directly to the affected area for 5-10 days. 1, 3
- For skin abscesses, incision and drainage remains the primary treatment, with mupirocin serving as adjunctive therapy. 4, 1
MRSA Nasal Decolonization
- For outbreak control and prevention, intranasal mupirocin (twice daily for 5-7 days) effectively eradicates MRSA nasal carriage. 4
- In cardiac surgery patients, applying 2% mupirocin to each nostril combined with chlorhexidine mouthwash starting at least 48 hours before surgery for a total of 5-7 days significantly reduces postoperative MRSA infections. 4
- For recurrent MRSA infections, applying mupirocin in the anterior nares twice daily for the first 5 days each month reduces recurrences by approximately 50%. 1
- One large study demonstrated 97% clearance of nasal MRSA carriage with calcium mupirocin treatment. 5
Important Limitations and Resistance Concerns
When Mupirocin Is NOT Appropriate
- Mupirocin is not suitable for extensive MRSA infections requiring systemic therapy. 1
- Deep soft tissue infections, complicated skin and soft tissue infections in hospitalized patients, and infections with systemic signs (fever, extensive cellulitis) require systemic antibiotics. 1
- For larger furuncles and all carbuncles with extensive surrounding cellulitis or fever, systemic antibiotics are indicated. 1
Resistance Patterns
- High-level mupirocin resistance (MIC >512 µg/mL) has been identified in S. aureus and is associated with treatment failure. 4
- Low-level resistance (MIC 8-256 µg/mL) is also problematic, with one study showing only 25% sustained clearance in patients with low-level resistant MRSA compared to 91% with susceptible strains. 6
- Mupirocin was effective in clearing mupirocin-susceptible MRSA in 78.5% of patients at day 3, but only 27.7% of patients with high-level resistant MRSA. 6
- In endemic MRSA settings, nasal mupirocin alone showed only marginal effectiveness for multisite MRSA carriage eradication (25% success rate). 7
Preventing Resistance Development
- Prolonged or indiscriminate use should be avoided to prevent resistance development. 1
- Regular surveillance for mupirocin susceptibility is appropriate before incorporating mupirocin into infection control programs, especially in settings with endemic MRSA. 6, 8
- Some facilities have reported mupirocin resistance in 1.43% of MRSA isolates among healthcare workers. 8
Optimal Decolonization Protocol
The most effective MRSA decolonization regimen combines multiple interventions: 4
- Intranasal mupirocin 2% twice daily for 5-7 days 4
- Daily chlorhexidine body washes 4
- Twice-daily chlorhexidine mouthwash for oropharyngeal decontamination 4
- Daily decontamination of personal items (towels, sheets) 1
This multimodal approach is more effective than mupirocin alone, particularly in endemic MRSA settings where single-agent nasal mupirocin showed limited efficacy. 7