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Source: Fish DN, Pendland SL, Danziger LH. Skin and Soft-Tissue Infections. In: DiPiro, JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey LM. Pharmacotherapy: A Pathophysiologic Approach. 8th ed. Accessed July 21, 2012.

  • Foot infections in patients with diabetes
  • Three types:
    • Deep abscesses
    • Cellulitis of the dorsum
    • Mal perforans ulcers

  • Begins with local bacterial invasion and is polymicrobic (average of 2.3–5.8 isolates per culture).
    • Most common pathogens: Staphylococci (especially S. aureus) and streptococci
    • Gram-negative bacilli and anaerobes occur in 50% of cases.

  • Key factors in development of diabetic foot problems (may occur in isolation or together):
    • Neuropathy
    • Angiopathy and ischemia
    • Immunologic defects that impair wound healing

  • One of most common diabetes complications, responsible for up to 20% of all hospitalizations of diabetics.

  • Optimize blood glucose control.
  • Encourage daily patient self-examination of feet.
  • Examine feet at every physician visit.

  • Uncontrolled blood glucose
  • Peripheral neuropathy

  • Infections often more extensive than they initially appear.
  • Clinical signs of infection may not be present secondary to angiopathy and neuropathy.

Signs and Symptoms

  • Swelling or erythema in foot (patient unaware of pain due to peripheral neuropathy)
  • Warmth
  • Presence of pus
  • Draining sinuses
  • Pain
  • Tenderness
  • Temperature: normal or mildly elevated
  • Lesions vary in size when present.
  • Four-smelling odor suggests anaerobic organisms.

Means of Confirmation and Diagnosis

  • Culture results

Laboratory Tests

  • Culture and sensitivities
    • Obtain specimen from deep culture, preferably expressed pus from wound base.
    • Culture for aerobic and anaerobic organisms.


  • Assess for osteomyelitis via radiograph, bone scan, or both, as appropriate

Diagnostic Procedures

  • Surgical debridement to obtain samples for culture and sensitivities

Differential Diagnosis

  • Preserve as much normal limb function as possible.
  • Prevent infectious complications.

  • Most infections successfully treated on outpatient basis with wound care and antibiotics.
  • Maximize glycemic control to ensure optimal wound healing.

  • Thoroughly debride necrotic tissue, with wound drainage and amputation as required.
  • Wounds must be kept clean and dressings changed 2–3 times daily.
  • Restrict patient initially to bedrest for leg elevation and control of edema, if present.
    • Adequate pressure relief from foot wound crucial to healing process.

  • Antimicrobial therapy (Tables 1 and 2)
    • Mild, uncomplicated infections treated with oral outpatient antibiotics such as amoxicillin-clavulanate.
      • Does not cover P. aeruginosa
      • Fluoroquinolones with metronidazole or clindamycin reasonable alternatives.
      • Treat 7–14 days.
    • Moderate to severe infections
      • Monotherapy with broad-spectrum parenteral antimicrobials plus appropriate medical and/or surgical management often effective (including those with presence of osteomyelitis).
        • Initial therapy similar to that for polymicrobic cellulitis with anaerobes.
        • Treat 2–4 weeks.
        • Treat 6–12 weeks if osteomyelitis is present.
        • Vancomycin used frequently in severe infections with gram-positive pathogens. With increasing staphylococcal resistance, linezolid, quinupristin/dalfopristin, daptomycin, and tigecycline are alternatives.

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