Diabetic Foot Infection

Michael Kaminski

VASP

Overview 

  • ALL superficial foot wounds are colonized with commensural flora; do not order superficial wound cultures on diabetic foot wounds. 
  • Usually polymicrobial GPCs (staph, strep), GNRs (PsA, Kleb), anaerobes 
  • Depth: superficial (skin and soft tissue) to deep (osteo) 
  • Do not give abx to clinically stable patients until operative cultures obtained.

Evaluation 

  • Assess Severity (IWGDF/IDSA 2023 classification system, page 14) 
  • Mark surrounding redness; vascular exam +/- ABIs for PAD, sensation for neuropathy; probe to bone test (high PPV)
  • X-rays for chronic osteo (>2W), MRI w/contrast for acute osteo (<2W); CRP/ESR trending (~weekly) 
  • BCx if systemic signs or severe infection. Consult podiatry if osteo for bone Cx (aerobic, anaerobic, myco, fungal) and histopath

Management 

  • Refer to VUMC ASP DFI Guidelines for specifics on abx dosing and duration 
  • PsA coverage: PsA on Cx, water exposure, hosp w/ IV abx past 90 days, immunocompromise 
  • MRSA coverage: MRSA on Cx, hosp w/ IV abx past 90 days, immunocompromise, IVDU, iHD 
  • Mild: target GPCs; Tx 1-2 weeks 
    • 1st Line: Cefadroxil, cephalexin, amox-clav 
    • MRSA or beta-lactam allergy: doxy, TMP-SMX 
  • Moderate/Severe: target GPCs, GNRs, +/- anaerobes; Tx ~1-2 weeks 
    • 1st Line: Amp-sulbactam, CTX+/-metro 
    • MRSA: Add vanc, TMPSMX, dapto, doxy, or linezolid 
    • PsA: Pip-tazo, Cefe, Levofloxacin; if c/f anaerobes: add metro 
  • If osteomyelitis, duration depends on surgery performed >> visit link above for duration 
  • Conversion to PO abx when clinically stable, functioning GI tract 
  • Discuss with ID fu plan, orals vs OPAT
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