• Infected diabetic foot ulcers demonstrate redness >0.5cm around the wound, heat, swelling, induration, pain, odour and purulence.

  • Infected ulcers fail to heal.

  • Do not culture uninfected ulcers, or treat uninfected ulcers with antibiotics.

  • Diagnosis of infection is based on examination, not culture.

Polymicrobial biofilms are not detected visually, but may be detected histologically.

Clinical features of biofilms include:

  • failure of antibiotic treatment

  • ulcer recurrence

  • implanted medical devices

  • negative culture

  • friable granulation tissue or undermining

  • prolonged inflammation

Topical and systemic antibiotics cannot treat biofilms, which require surgical debridement.

Tissue specimens are preferred over swabs for culture diagnosis. Bone culture is the most informative. Bone culture-based treatment is associated with increased remission rate (Senniville Diabetes Care 2008).

Collect blood culture for systemic infections. Take x-ray or probe to bone to diagnose osteomyelitis. Nuclear medicine scans are generally not helpful for diagnosis.

IWGDF Classification

Infected wound involving skin and subcutaneous tissue, no systemic features.

Infected wound involving tendon, bone, muscle, joint, no systemic features.

Infected wound with >=2 SIRS criteria.