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

Mupirocin Nasal Ointment for Staphylococcus aureus Eradication

Apply mupirocin 2% ointment to the anterior nares twice daily for 5 days to eradicate nasal colonization of Staphylococcus aureus, including MRSA. 1, 2

Standard Decolonization Regimen

• The FDA-approved and guideline-recommended dosage is 0.5 grams inserted into each nostril twice daily for 5 days (total of 10 doses). 1, 2
• This 10-dose regimen achieves 89.5% sustained decolonization for at least 4 weeks post-treatment, which is significantly superior to shorter 6-dose regimens (68% success rate). 3
• Local concentrations exceed inhibitory levels for staphylococci and remain detectable for up to 72 hours after application. 2

When to Use Nasal Mupirocin

Routine decolonization of asymptomatic MRSA nasal carriers is NOT recommended. 1 Treatment should be reserved for specific scenarios:

• Recurrent skin and soft tissue infections that persist despite optimizing 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
• As part of comprehensive infection-control programs during institutional MRSA outbreaks 2
• Pre-operative decolonization in surgical patients who are S. aureus carriers, especially MRSA carriers 3

Essential Concurrent Decolonization Measures

Mupirocin alone is insufficient. Combine with:

• Topical body decolonization with chlorhexidine for 5-14 days or dilute bleach baths (1/4 to 1/2 cup bleach per full bathtub) 1
• Keep draining wounds covered with clean, dry bandages 1
• Hand hygiene with soap and water or alcohol-based gel after touching infected areas 1
• Avoid sharing personal items and clean high-touch surfaces with commercial cleaners 1
• Treat interdigital toe space infections/maceration to reduce colonization reservoirs 1

Household Contact Management

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

Efficacy by Resistance Pattern

The effectiveness of mupirocin varies dramatically based on mupirocin susceptibility:

• Mupirocin-susceptible MRSA: 91% sustained clearance at 1-4 weeks 4
• Low-level mupirocin-resistant MRSA: Only 25% sustained clearance 4
• High-level mupirocin-resistant MRSA: Only 25% sustained clearance, with just 27.7% achieving initial clearance at day 3 4

Critical Limitations and Resistance Concerns

• High-level mupirocin resistance has been reported in some community settings, and prolonged or indiscriminate use should be avoided to prevent resistance development 1
• Mupirocin effectively reduces nasal colonization but has not conclusively been shown to prevent infections in community settings 1
• It is appropriate to sample MRSA populations for mupirocin susceptibility prior to incorporating mupirocin into infection control programs, particularly in settings where mupirocin-resistant MRSA is prevalent 4

When Mupirocin is NOT Appropriate

• Extensive infections requiring systemic therapy 5
• Deep soft tissue infections or complicated skin and soft tissue infections in hospitalized patients 5
• Cutaneous abscesses as primary treatment (incision and drainage is required) 5
• Minor skin infections in children can use mupirocin 2% topical ointment for impetigo and secondarily infected skin lesions (eczema, ulcers, lacerations), but this is for skin application, not nasal decolonization 6

Monitoring and Follow-up

• Screening cultures are not routinely recommended, and 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
• If recurrent infections continue despite decolonization, consider that mupirocin resistance may be present or that other body sites (not just nares) are colonized 4