What is the recommended empiric antibiotic therapy for bacterial skin and soft tissue infections (SSTI)?

Empiric Antibiotic Therapy for Bacterial Skin and Soft Tissue Infections (SSTIs)

The recommended empiric antibiotic therapy for bacterial skin and soft tissue infections should be tailored to the specific type of infection, with consideration of local MRSA prevalence and clinical presentation severity. 1

Classification and Initial Management Approach

• SSTIs should first be classified as purulent (abscess, furuncle, carbuncle) or non-purulent (cellulitis, erysipelas) to guide appropriate empiric therapy 1
• Incision and drainage is the primary treatment for purulent SSTIs, with antibiotics as adjunctive therapy for more severe infections 1

Empiric Antibiotic Recommendations by SSTI Type

Purulent SSTIs (likely Staphylococcus aureus)

• Outpatient treatment options:

  • Clindamycin 1
  • Trimethoprim-sulfamethoxazole (TMP-SMX) 1
  • Tetracyclines (doxycycline or minocycline) 1
  • Linezolid 1

• For coverage of both MRSA and β-hemolytic streptococci:

  • Clindamycin alone 1
  • TMP-SMX or tetracycline plus amoxicillin 1
  • Linezolid alone 1

Non-purulent SSTIs (likely β-hemolytic streptococci)

• First-line options:
  • Benzylpenicillin or phenoxymethylpenicillin 1
  • Clindamycin 1
  • Nafcillin 1
  • Cefazolin or cefalexin 1

Complicated SSTIs (hospitalized patients)

• Intravenous options:
  • Vancomycin 1
  • Linezolid (oral or IV) 1
  • Daptomycin 1
  • Telavancin 1
  • Clindamycin (oral or IV) 1

Special Considerations

Necrotizing Fasciitis

• Recommended empiric therapy:
  • Clindamycin plus piperacillin-tazobactam (with or without vancomycin) 1
  • Ceftriaxone plus metronidazole (with or without vancomycin) 1
  • Vancomycin or linezolid plus piperacillin-tazobactam or a carbapenem 1

Diabetic Foot Infections

• Mild infections:

  • Dicloxacillin, clindamycin, cefalexin, levofloxacin, amoxicillin-clavulanic acid, or doxycycline 1
  • For suspected MRSA: TMP-SMX 1

• Moderate to severe infections:

  • Levofloxacin, cefoxitin, ceftriaxone, ampicillin-sulbactam, ertapenem, tigecycline 1
  • For suspected MRSA: linezolid, daptomycin, or vancomycin 1
  • For potential Pseudomonas aeruginosa: piperacillin-tazobactam, ceftazidime, cefepime, aztreonam, or carbapenems 1

Considerations for MRSA Coverage

• Include empiric MRSA coverage if:
  • Local MRSA prevalence exceeds 10-15% 2
  • Patient has risk factors for MRSA (prior MRSA infection, recent hospitalization, recent antibiotic use) 1
  • Patient presents with purulent infection 1
  • Patient has failed initial β-lactam therapy 1

Duration of Therapy

• 5-7 days is typically adequate for most uncomplicated SSTIs 3
• Duration may be extended for complicated infections, immunocompromised hosts, or inadequate source control 1

Important Clinical Pearls

• Obtain bacterial cultures from abscesses and purulent SSTIs before starting antibiotics to guide definitive therapy 1
• Consider local antibiotic resistance patterns when selecting empiric therapy 1
• Reassess therapy within 48-72 hours to determine clinical response and adjust antibiotics based on culture results 3
• For recurrent SSTIs, consider decolonization strategies with mupirocin nasal ointment and chlorhexidine body washes 1

Antibiotic Selection Algorithm

1. Assess infection type: Purulent vs. non-purulent
2. Determine severity: Mild, moderate, or severe/complicated
3. Consider local MRSA prevalence: If >10%, include MRSA coverage 2
4. Evaluate patient factors: Immunocompromised status, drug allergies, prior antibiotic exposures
5. Select appropriate antibiotic based on above factors
6. Reassess in 48-72 hours and adjust therapy as needed