Community-acquired MRSA

Empiric Therapy

Empiric ORAL Theray for CA-MRSA (7-10 days)

TMP-SMX 1-2 DS tabs PO BID
Doxycycline 100 mg PO BID with food
Clindamycin 600 mg PO TID (less than 50 kg and gastro upset try 300 mg PO QID)

If RECURRENT CA-MRSA infection consider adding:

Rifampin 600 mg daily or 300 mg PO BID

If Group A Streptococcal (GAS) infection suspected (e.g. rapid onset, lymphangitic streaking, regional lymphadenopathy) and patient NOT already receiving clindamycin, consider ADDING GAS-effective agent:

Cephalexin 500 mg PO QID
Penicillin VK 300 mg PO QID

Severe pen-allergy or cephalosporin allergy (e.g. anaphylaxis, angioedemia)

Clindamycin 600 mg PO TID (less than 50 kg and gastro upset try 300 mg PO QID)

  • Approximately 30% of CA-MRSA strains in VIHA are non-susceptible to clindamycin. Clindamycin should NOT be used as single empiric coverage for moderately severe infections.

Empiric PARENTERAL Therapy for CA-MRSA (7-10 days)

To be used in combination with a single ORAL agent for treatment of moderate/severe infections associated with systemic features.

Vancomycin 15 mg/kg IV q12h (assuming normal renal function)
Target trough levels of 10-15 mg/L

Consider adding agent that inhibits protein synthesis for life- and/or limb-threatening infections including necrotizing fasciitis, pyomyositis, septic shock, and Staphylococcal toxic shock syndrome:
Clindamycin 600-900 mg IV q8h
See Discussion


To address the problem of CA-MRSA skin & soft-tissue infections within the health authority, the VIHA Antimicrobial Review Subcommittee has developed a detailed treatment algorithm for adult and pediatric patients which can be accessed here. CA-MRSA Treatment Algorithm

Usual Features of SSTI suggestive of CA-MRSA The index of suspicion should be increased when a patient has 1 or more known epidemiologic risk factors and a consistent clinical presentation with CA-MRSA

Risk factors for CA-MRSA infection:

  • Intravenous drug use.
  • Homelessness / incarceration.
  • Aboriginal descent.
  • Participation in close contact sports.
  • Known close contact with individuals at higher risk.
  • History of MRSA infection / colonization.
  • Children < 2 years.
  • Men who have sex with men.

Characteristic clinical presentation:

  • Folliculitis, furuncles/carbuncles, abscesses, and/or cellulitis.
  • Simultaneous presence of two or more pustules, often at unrelated sites. Pustules are often painful and may or may not be associated with cellulitis.

Key Points

  • If CA-MRSA suspected, always collect specimen(s) for culture and sensitivity
  • Systemic antibiotics are often unnecessary for localized disease with no systemic features.
  • There is no clinical data to support combination therapy over monotherapy. Reserve combination therapy for severe infection.
  • Rifampin should never be used on its own due to the potential for rapid development of resistance.