What is the treatment for a Staphylococcus (Staph) infection in the nares?

Treatment of Staphylococcus Infection in the Nares

For active staph infection in the nares, treat with mupirocin 2% ointment applied to both anterior nares twice daily for 5-10 days, combined with appropriate systemic antibiotics if there are signs of invasive infection. 1, 2

Distinguishing Active Infection from Colonization

• Active infection presents with purulent drainage, crusting, pain, erythema, or systemic signs (fever, malaise), requiring antimicrobial treatment 1
• Asymptomatic colonization (positive nasal swab without symptoms) does not require routine treatment unless specific criteria are met 2, 3

Treatment for Active Nasal Staph Infection

Topical Therapy

• Apply mupirocin 2% ointment to both anterior nares twice daily for 5-10 days as the primary topical agent 2, 3, 4
• Mupirocin is bactericidal against S. aureus (including MRSA) and works by inhibiting bacterial protein synthesis through a unique mechanism with no cross-resistance to other antimicrobials 4, 5
• The medication achieves high local concentrations with minimal systemic absorption (<1.1 ng/mL in whole blood) 4

Systemic Antibiotics (When Indicated)

• Add systemic antibiotics if there is extensive surrounding cellulitis, fever, or systemic manifestations of infection 1
• For MSSA infections with systemic involvement: nafcillin 1-2 g IV every 4-6 hours (adults) or 50 mg/kg/dose (pediatrics) 1
• For MRSA infections with systemic involvement: vancomycin, linezolid, daptomycin, or ceftaroline based on severity 1
• Duration of systemic therapy is typically 5-7 days depending on clinical response 1

Decolonization for Recurrent Infections

Decolonization should only be pursued in patients with documented recurrent staph skin infections despite optimized hygiene, or ongoing household transmission—not for simple colonization. 2, 3

Decolonization Protocol

• Mupirocin 2% ointment to anterior nares twice daily for 5-10 days 2, 3
• Add chlorhexidine gluconate 2% body wash daily for 5-14 days, OR dilute bleach baths (¼-½ cup bleach per full bathtub or 1 teaspoon per gallon) for 15 minutes twice weekly for up to 3 months 2, 3
• Concurrent measures: keep wounds covered with clean dry bandages, practice hand hygiene after touching infected areas, avoid sharing personal items, clean high-touch surfaces regularly 3
• Treat interdigital toe space infections/maceration to eliminate colonization reservoirs 3

Household Contact Management

• Evaluate and treat symptomatic household contacts for active infection first 2, 3
• Consider decolonization of asymptomatic household contacts only when ongoing transmission is documented despite hygiene measures 2, 3
• Treating both patient and household contacts together results in fewer recurrences than treating the patient alone 3

Alternative Agents (When Mupirocin Unavailable or Resistant)

• Povidone-iodine nasal antiseptic preparations show efficacy against mupirocin-resistant MRSA with rapid antimicrobial activity within 1 hour 6
• Chlorhexidine/neomycin (Naseptin) cream is less effective than mupirocin, with only 61% eradication at 8 days versus 95% with mupirocin, and higher recolonization rates (89% versus 43%) 7

Important Caveats and Pitfalls

• Do not use mupirocin for simple nasal trauma or cuts without signs of infection—this promotes resistance without clinical benefit 8
• Avoid routine surveillance cultures post-decolonization in the absence of active infection 2, 3
• High-level mupirocin resistance (MIC >1024 mcg/mL) has been reported; prolonged or indiscriminate use should be avoided 3, 4
• Recolonization is common after decolonization therapy, occurring in 40-60% of patients within 3 months, often with exogenous strains 9, 7
• Extranasal carriage sites (pharynx, perineum, axillae, groin) are common (19-23% prevalence) and mupirocin is less effective at clearing these sites, contributing to treatment failure 9
• Do not use hexachlorophane in children under 2 months due to neurological complications 2
• Mupirocin effectively reduces nasal colonization but has not conclusively been shown to prevent infections in community settings 3