What are the first-line and second-line treatment options for Methicillin-resistant Staphylococcus aureus (MRSA) skin infections?

First-Line and Second-Line Treatment Options for MRSA Skin Infections

For MRSA skin infections, incision and drainage is the primary treatment for abscesses, with oral trimethoprim-sulfamethoxazole, doxycycline, or clindamycin as first-line antibiotic options, and linezolid as the preferred second-line therapy. 1

Primary Treatment Approach

• Incision and drainage is the cornerstone of treatment for cutaneous abscesses caused by MRSA, and for simple abscesses or boils, this procedure alone may be adequate without antibiotics 1
• For minor skin infections (such as impetigo) and secondarily infected skin lesions, mupirocin 2% topical ointment may be effective 2
• Antibiotic therapy should be added to incision and drainage when any of these factors are present:
  • Severe or extensive disease or rapid progression with associated cellulitis
  • Signs of systemic illness
  • Comorbidities or immunosuppression
  • Extremes of age
  • Abscess in difficult-to-drain areas (face, hand, genitalia)
  • Associated septic phlebitis
  • Lack of response to incision and drainage alone 1, 2

First-Line Oral Antibiotic Options

• Trimethoprim-sulfamethoxazole (TMP-SMX) (1-2 double-strength tablets twice daily for adults):

  • Highly effective against MRSA
  • Limited coverage of β-hemolytic streptococci
  • Multiple studies support its efficacy for MRSA skin infections 1, 2

• Doxycycline (100 mg twice daily for adults):

  • Effective first-line option for MRSA
  • Contraindicated in children under 8 years of age
  • Several observational studies and small trials support its effectiveness 1, 2

• Clindamycin (300-450 mg three times daily for adults):

  • Advantages include coverage of both MRSA and β-hemolytic streptococci
  • Caution needed for potential cross-resistance in erythromycin-resistant strains
  • Particularly effective in children with MRSA skin infections 1, 2

Second-Line Antibiotic Option

• Linezolid (600 mg twice daily for adults):
  • Recommended when first-line options fail or for serious infections
  • FDA-approved for MRSA skin infections
  • No cross-resistance with other antibiotic classes
  • Limitations include high cost and potential for adverse effects
  • Not superior to less expensive alternatives for uncomplicated infections 1, 2

Intravenous Options for Severe Infections

• Vancomycin is the recommended treatment for complicated MRSA skin infections requiring hospitalization:
  • Indicated for serious or severe infections caused by MRSA
  • Effective for skin and skin structure infections due to staphylococci
  • Should be used when patients have systemic toxicity or rapidly progressive infections despite oral antibiotics 3, 2

Duration of Therapy

• 5-10 days of therapy is recommended for most MRSA skin infections
• 7-14 days may be needed for complicated infections 1

Special Considerations for Pediatric Patients

• For children with MRSA skin infections:
  • Clindamycin 10-13 mg/kg/dose IV every 6-8 hours (to administer 40 mg/kg/day) is an option if clindamycin resistance is low
  • Linezolid 10 mg/kg/dose every 8 hours for children <12 years of age is an alternative 2

Common Pitfalls to Avoid

• Do not use rifampin as monotherapy or adjunctive therapy for MRSA skin infections, as resistance develops rapidly 1, 2
• Do not rely on beta-lactam antibiotics (including penicillins and cephalosporins) for MRSA infections, as they are ineffective 4
• Always obtain cultures from abscesses in patients receiving antibiotic therapy to guide treatment, especially with increasing resistance patterns 1
• Do not overlook the importance of adequate drainage for purulent infections, as antibiotics alone may be insufficient 5

Prevention of Recurrence

• Keep draining wounds covered with clean, dry bandages
• Maintain good personal hygiene with regular handwashing
• Focus cleaning on high-touch surfaces to reduce the risk of MRSA recurrence 1