Community – acquired MRSA

Empiric Therapy

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

TMP-SMX 1-2 DS tabs PO BID
OR
Doxycycline 100 mg PO BID with food
OR
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
OR
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

Background

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.

Category: Skin and Soft Tissue Infections

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