What is the treatment for a rare gram-positive cocci infection treated with Bactroban (mupirocin)?

Treatment of Gram-Positive Cocci with Bactroban (Mupirocin)

For localized gram-positive cocci infections, topical mupirocin 2% ointment applied three times daily for 3-10 days is appropriate first-line therapy, particularly for mild superficial skin infections such as impetigo or small infected wounds caused by susceptible organisms like Staphylococcus aureus and Streptococcus pyogenes 1.

Clinical Application and Dosing

• Apply a small amount of mupirocin ointment to the affected area three times daily 1
• The treated area may be covered with gauze dressing if desired 1
• Re-evaluate patients who do not show clinical response within 3-5 days, as this indicates need for alternative therapy 1
• Treatment duration typically ranges from 5-10 days for most superficial infections 2, 3

When Mupirocin is Most Appropriate

Mupirocin is specifically indicated for:

• Mild, localized superficial skin infections where gram-positive cocci are the primary pathogen 4
• Impetigo and small infected wounds/lacerations, where clinical cure rates exceed 80-90% 3, 5, 6
• Nasal decolonization of MRSA carriers using intranasal formulation twice daily for 5-10 days 2, 7
• Neonatal pustulosis with localized disease in full-term infants 4

Spectrum and Limitations

• Mupirocin has excellent activity against aerobic gram-positive cocci including methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis, and Streptococcus pyogenes 1, 3
• It demonstrates no cross-resistance with other antibiotic classes due to its unique mechanism (inhibition of bacterial isoleucyl-tRNA synthetase) 1, 5
• Mupirocin is NOT formulated for mucosal surfaces and the topical ointment should not be used intranasally 1

When to Escalate Beyond Topical Therapy

Switch to systemic antibiotics if:

• Infection involves deeper structures, multiple sites, or extensive areas 4
• Patient has systemic signs (fever, hypotension, cardiovascular impairment) 4
• No clinical improvement after 3-5 days of topical therapy 1
• Infection occurs in premature/very low-birthweight infants 4
• Moderate-to-severe infections requiring broader coverage 4

For moderate-to-severe infections, the Infectious Diseases Society of America recommends empirical therapy targeting aerobic gram-positive cocci with agents such as oral clindamycin, TMP-SMX, doxycycline, or linezolid for outpatient management, or IV vancomycin, daptomycin, or linezolid for hospitalized patients 4.

Critical Precautions

• Avoid use in patients with moderate-to-severe renal impairment when treating large open wounds, as the polyethylene glycol vehicle can be absorbed and is renally excreted 1
• Discontinue if irritation, severe itching, or rash develops 1
• Prolonged use may result in overgrowth of nonsusceptible organisms including fungi 1
• High-level mupirocin resistance (MIC >1024 mcg/mL) has been reported in some staphylococcal strains, though it remains rare 1

Comparative Efficacy

Clinical trials demonstrate mupirocin achieves clinical cure or marked improvement in over 80% of patients with primary skin infections, with bacterial eradication rates exceeding 90% 3, 5. In head-to-head comparisons, mupirocin showed significantly better clinical response than erythromycin (86% vs 47% cure rate) and similar efficacy to flucloxacillin (86% vs 76% cure rate) for impetigo and infected wounds 6.