What is the role of Bactroban (mupirocin) in treating skin infections?

Role of Bactroban (Mupirocin) in Treating Skin Infections

Mupirocin 2% ointment (Bactroban) is the first-line topical treatment for localized impetigo and other limited skin infections caused by Staphylococcus aureus and Streptococcus pyogenes. 1, 2

Mechanism of Action and Antimicrobial Coverage

• Mupirocin works by inhibiting bacterial protein synthesis through reversible and specific binding to bacterial isoleucyl transfer-RNA synthetase 2
• Highly effective against:
  • Staphylococcus aureus (including MRSA)
  • Streptococcus pyogenes
  • Staphylococcus epidermidis
  • Staphylococcus saprophyticus 2

Clinical Indications

Primary Indication

• FDA-approved for topical treatment of impetigo due to S. aureus and S. pyogenes 2

Other Evidence-Supported Uses

• Limited folliculitis
• Small superficial skin infections
• Secondary infected dermatitis when localized 1
• Eradication of nasal MRSA colonization (mupirocin nasal formulation) 3

Treatment Guidelines

For Impetigo:

1. Limited lesions: Topical mupirocin 2% ointment applied three times daily for 5 days 4, 1
2. Numerous or widespread lesions: Consider oral antibiotics instead 4, 1
3. During outbreaks: Systemic antibiotics preferred to decrease transmission 4

Efficacy Comparison:

• Topical mupirocin is slightly more effective than oral erythromycin 4
• Similar efficacy to fusidic acid cream for S. aureus infections but superior for S. pyogenes 5
• Comparable to oral flucloxacillin but more effective than oral erythromycin 5

Administration

• Apply a small amount to the affected area three times daily 2, 6
• Average treatment duration: 5-7 days for topical therapy 1
• Cover lesions when possible to prevent spread 1

Advantages of Topical Mupirocin

1. Minimal systemic absorption (<1.1 ng/mL in blood) 2
2. Fewer systemic side effects than oral antibiotics 7
3. Lower cost than systemic therapy 7
4. Reduced risk of inducing widespread antibiotic resistance 7
5. Unique mechanism of action with no cross-resistance to other antibiotic classes 2

Limitations and Precautions

1. Not for extensive infections: Oral antibiotics preferred for numerous lesions 4, 1
2. Resistance concerns: High-level resistance has been reported in some S. aureus strains 2
3. Not for deep tissue infections: Only effective for superficial skin infections 1
4. Renal impairment: Use with caution in moderate to severe renal impairment due to polyethylene glycol in the base 1

Adverse Effects

• Local reactions occur in approximately 3% of patients 6:
  • Burning
  • Itching
  • Redness
  • Dry skin 8
• No evidence of systemic toxicity or abnormal laboratory values 6

When to Consider Alternative Therapy

• For widespread infections
• When treatment fails after 3-5 days
• For suspected deep tissue involvement
• For systemic symptoms
• During outbreaks affecting multiple people 4, 1

In summary, mupirocin (Bactroban) is a highly effective topical antibiotic for localized skin infections, particularly impetigo, with excellent activity against the most common causative pathogens and minimal systemic effects. For more extensive infections, systemic antibiotics should be considered instead.