What is the recommended treatment for eradicating nasal colonization with Methicillin-resistant Staphylococcus aureus (MRSA) using mupirocin nasal ointment?

Mupirocin Nasal Ointment for MRSA Decolonization

Apply mupirocin 2% ointment to the anterior nares twice daily for 5-10 days to eradicate MRSA nasal colonization, but only pursue decolonization in specific clinical scenarios—not routinely for asymptomatic carriers. 1

When to Treat MRSA Nasal Colonization

Decolonization should be reserved for specific situations, not performed routinely:

• Recurrent skin and soft tissue infections that persist despite optimized wound care and hygiene measures 1
• Ongoing transmission among household members or close contacts despite hygiene interventions 1
• Following treatment of active infection in symptomatic patients 1
• During institutional outbreaks as part of comprehensive infection-control programs 2

Do not routinely decolonize asymptomatic MRSA nasal carriers outside these specific scenarios. 1

Recommended Decolonization Regimen

Standard Protocol

• Mupirocin 2% ointment: Apply approximately 0.5 grams into each nostril twice daily for 5-10 days 1, 2
• The 10-dose regimen (5 days, twice daily) is superior to shorter 6-dose regimens, maintaining decolonization for at least 4 weeks post-therapy (89.5% vs 68.0% success rate, p=0.016) 3

Enhanced Approach for Recurrent Cases

For patients with recurrent infections, combine mupirocin with topical body decolonization: 1

• Mupirocin 2% ointment to anterior nares twice daily for 5-10 days 1
• Plus chlorhexidine body washes for 5-14 days 1
• Or dilute bleach baths: 1/4 to 1/2 cup bleach per full bathtub 1

This combined strategy is suggested by the Infectious Diseases Society of America when single-agent decolonization is being considered. 4

Essential Concurrent Hygiene Measures

Decolonization will fail without these critical interventions:

• Cover draining wounds with clean, dry bandages 1
• Hand hygiene with soap and water or alcohol-based gel after touching infected areas 1
• Avoid sharing personal items (towels, razors, clothing) 1
• Clean high-touch surfaces with commercial cleaners 1
• Treat interdigital toe space infections/maceration to eliminate colonization reservoirs 1
• Daily decontamination of personal items like towels and sheets 5

Household Contact Management

When ongoing transmission is documented:

• Evaluate symptomatic contacts first and treat active infections 1
• Consider simultaneous decolonization of both patient and household contacts together, which results in fewer recurrences than treating the patient alone 1
• Asymptomatic household contacts may be considered for decolonization when ongoing transmission is documented 1

Critical Limitations and Resistance Concerns

Efficacy Against Resistant Strains

Mupirocin effectiveness depends heavily on susceptibility status:

• Mupirocin-susceptible MRSA: 91% sustained clearance at 1-4 weeks 6
• Low-level mupirocin-resistant MRSA: Only 25% sustained clearance 6
• High-level mupirocin-resistant MRSA: Only 25% sustained clearance, with 72.3% showing persistent colonization at day 3 6

Resistance Development

• High-level mupirocin resistance has been reported in some community settings 1
• Avoid prolonged or indiscriminate use to prevent resistance development 1
• Treatment failure with mupirocin-resistant strains typically reflects true resistance rather than exogenous recolonization 6

Testing Considerations

• Screening cultures are not routinely recommended 1
• Pre-decolonization cultures are unnecessary if prior MRSA infection was documented 1
• Post-decolonization surveillance cultures are not recommended in the absence of active infection 1
• However, it may be appropriate to sample MRSA populations for mupirocin susceptibility prior to incorporating mupirocin into infection control programs, particularly in settings with known resistance 6

Important Caveats

• Mupirocin effectively reduces nasal colonization but has not conclusively been shown to prevent infections in community settings 1
• The evidence base for preventing subsequent skin infections with nasal decolonization alone is limited 5
• Oral antimicrobials are not routinely recommended for decolonization and should only be considered in patients who continue to have infections despite other measures 4
• If oral agents are used, a rifampin-based combination (e.g., with TMP-SMX or doxycycline) administered for short courses (5-10 days) is suggested 4