What does Mupiricin (mupirocin) treat?

What Does Mupirocin Treat?

Mupirocin is a topical antibiotic indicated for the treatment of impetigo caused by Staphylococcus aureus and Streptococcus pyogenes, and it also has a role in treating other minor superficial skin infections and in decolonizing nasal carriage of S. aureus, including MRSA. 1

Primary FDA-Approved Indication

• Impetigo: Mupirocin ointment 2% is FDA-approved specifically for topical treatment of impetigo due to Staphylococcus aureus and Streptococcus pyogenes 1
• Applied 2-3 times daily to affected areas 2

Additional Clinical Uses Supported by Guidelines

Minor Skin Infections in Children and Adults

• Mupirocin 2% topical ointment is recommended for children with minor skin infections such as impetigo and secondarily infected skin lesions (eczema, ulcers, or lacerations) 2
• The IDSA guidelines (2011) specifically endorse topical mupirocin for these pediatric indications 2

Localized Nonbullous Impetigo

• Topical mupirocin is the best topical agent for impetigo treatment 2
• The 2005 IDSA guidelines note that mupirocin is superior to alternatives like bacitracin and neomycin, which are considerably less effective 2
• A 2012 systematic review found topical mupirocin was slightly more effective than oral erythromycin (RR 1.07,95% CI 1.01-1.13) 2

Nasal Decolonization for S. aureus (Including MRSA)

• Intranasal mupirocin applied twice daily for 5-7 days can be used for eradication of nasal S. aureus colonization, including MRSA strains 2
• The 2014 IDSA guidelines note that older trials showed twice-daily intranasal mupirocin for 5 days each month reduced rates of recurrent skin infections 2
• However, one randomized trial in military personnel found that nasal mupirocin alone did not reduce subsequent skin infections in MRSA carriers 2
• A 5-day decolonization regimen combining twice-daily intranasal mupirocin with daily chlorhexidine or dilute bleach bathing may be considered for prevention of recurrent skin infections, though efficacy data are sparse 2

Important Caveats and Limitations

When Systemic Therapy is Preferred

• For patients with numerous lesions or in outbreak settings, systemic oral antibiotics are preferred over topical mupirocin to help decrease transmission 2
• Topical therapy alone may be insufficient for widespread disease 2

Resistance Concerns

• High-level (MIC >512 µg/mL) and low-level (MIC 8-256 µg/mL) mupirocin resistance has been identified in S. aureus, with high-level resistance associated with decolonization failure 2
• Resistance occurs rarely but can result from production of modified isoleucyl-tRNA synthetase 1

Limited Spectrum

• Mupirocin has excellent activity against staphylococci and most streptococci but less activity against other gram-positive and most gram-negative bacteria 1, 3
• It should not be used for infections likely caused by gram-negative organisms 1

Not for Deep or Complicated Infections

• Mupirocin is only for superficial skin infections 1
• It demonstrates no measurable systemic absorption (<1.1 ng/mL) after topical application, making it unsuitable for deeper infections 1

Mechanism and Unique Properties

• Mupirocin inhibits bacterial protein synthesis by reversibly binding to bacterial isoleucyl transfer-RNA synthetase 1
• This unique mechanism means it demonstrates no in vitro cross-resistance with other antimicrobial classes 1
• It is bactericidal at concentrations achieved by topical administration, though the MBC is generally 8-30 fold higher than the MIC 1