Diabetic Foot Infection

Paul Auwaerter, M.D.


  • Most diabetic foot infections (DFIs) are polymicrobial; however, if the patient hasn’t recently received abx therapy, it is often monomicrobial due to staphylococcal or streptococcal infection.
  • Frequent pathogens: based on deep wound or bone cultures. Pathogens recovered from superficial swabs should be viewed with suspicion.
  • Superficial, early infections (cellulitis, cellulitis involving blisters and shallow ulcers) are typically caused by S. aureus or beta-hemolytic streptococci.
  • Infections of ulcers that are chronic or previously treated with antibiotics may be caused by aerobic Gram-negative bacilli, S. aureus or Streptococci.
  • Deep soft tissue infections, osteomyelitis, and gangrene are more often polymicrobial, including aerobic Gram-negative bacilli and anaerobes (anaerobic streptococci, Bacteroides fragilis group, Clostridium species), but Staphylococcus aureus is also common as a single pathogen.
  • Multi-drug resistant Gram-negative organisms described in DFI, especially ESBL, but most resistant organisms w/ reports from India and warmer climates.

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Last updated: March 10, 2024