What antibiotics are best for treating diabetic foot ulcers?

From the Guidelines

For foot ulcers, the best antibiotic treatment is to use any of the systemic antibiotic regimens that have been shown to be effective in published randomised controlled trials at standard (usual) dosing, such as amoxicillin-clavulanate, cephalexin, or trimethoprim-sulfamethoxazole, for a duration of 1–2 weeks, with consideration of continuing treatment for up to 3–4 weeks if the infection is improving but is extensive and is resolving slower than expected. The choice of antibiotic should be based on the severity and type of infection present, as well as local resistance patterns, and should be adjusted based on culture results, as many foot ulcers contain multiple bacteria including anaerobes and sometimes MRSA, which may require addition of vancomycin or linezolid 1. Some key points to consider when selecting an antibiotic regimen include:

• The severity of the infection, with mild infections typically responding well to oral antibiotics and moderate to severe infections requiring broader coverage with options such as ciprofloxacin plus clindamycin or piperacillin-tazobactam 1
• The likely or proven causative pathogens, with aerobic gram-positive cocci being the most common causative organisms in diabetic foot infections 1
• The clinical severity of the infection, with more severe infections requiring longer treatment courses and broader coverage 1
• The need for proper wound care, including debridement of dead tissue, offloading pressure from the ulcer, and managing underlying conditions like diabetes, in addition to antibiotic therapy 1. It's also important to note that the duration of antibiotic therapy should be based on the resolution of findings of infection, and not through complete healing of the wound, and that the treatment should be re-evaluated if evidence of infection has not resolved after 4 weeks of apparently appropriate therapy 1.

From the FDA Drug Label

1. 3 Skin and Skin Structure Infections Piperacillin and Tazobactam for Injection is indicated in adults for the treatment of uncomplicated and complicated skin and skin structure infections, including cellulitis, cutaneous abscesses and ischemic/diabetic foot infections caused by beta-lactamase producing isolates of Staphylococcus aureus.

Piperacillin-tazobactam is an antibiotic that can be used to treat foot ulcers, specifically ischemic/diabetic foot infections caused by beta-lactamase producing isolates of Staphylococcus aureus 2.

From the Research

Antibiotics for Foot Ulcers

• The most effective antibiotics for foot ulcers are not universally agreed upon, but some studies suggest the following options:
  • Vancomycin, although its use may increase the risk of antibiotic-induced nephrotoxicity 3
  • Combination therapy with vancomycin and Zosyn, which also increases the potential risk of nephrotoxicity 3
  • Alternative antibiotics with broad-spectrum coverage and minimal nephrotoxicity, such as:
    • Ceftriaxone 3
    • Clindamycin 3, 4
    • Metronidazole 3
    • Amoxicillin-clavulanate 3
    • Linezolid 3
• Oral antibiotics, such as clindamycin and ciprofloxacin, may be effective in treating diabetic foot infections and reducing hospital stay 4

Topical Antimicrobial Agents

• Topical antimicrobial agents, such as antimicrobial dressings, may increase the number of diabetic foot ulcers healed over a medium-term follow-up period 5
• The use of topical antimicrobial agents may have little difference in the risk of adverse events compared to systemic antibiotics 5
• Emerging treatments, such as molecular and regenerative medicine, antimicrobial and energy-based therapies, and the use of plant extracts, antimicrobial peptides, growth factors, ozone, devices, and nano-medicine, may offer new approaches in the management and treatment of diabetic foot ulcers 6, 7

Treatment Approaches

• A multidisciplinary approach, including patient education, use of appropriate diagnostic tools, and expertise, is necessary for the treatment of diabetic foot ulcers 7
• Individualized antimicrobial driven treatment, routine debridement, regular wound examination, and dressing changes may help prevent amputations and promote wound healing 7
• New biological and molecular therapies may enhance infection prevention, management of the local inflammatory profile, and the efficiency of the cicatrizing mechanism 7