What antibiotics are used to treat diabetic foot ulcers?

From the Guidelines

Antibiotic treatment for diabetic foot ulcers should be tailored to the severity of infection and likely pathogens, with the most recent guidelines from 2024 (1) emphasizing the importance of considering local resistance patterns and adjusting treatment based on culture results. When managing diabetic foot ulcers, it's crucial to understand that the treatment approach must be multifaceted, including not just antibiotics but also proper wound care, offloading pressure, glycemic control, and vascular assessment.

• For mild infections, oral antibiotics such as amoxicillin-clavulanate (875/125 mg twice daily), cephalexin (500 mg four times daily), or trimethoprim-sulfamethoxazole (1-2 DS tablets twice daily) for 7-14 days are typically effective, as suggested by previous guidelines (1).
• Moderate infections may require broader coverage with fluoroquinolones like ciprofloxacin (500-750 mg twice daily) plus clindamycin (300-450 mg four times daily) for 14-21 days.
• Severe infections necessitate intravenous therapy with options including piperacillin-tazobactam (4.5 g every 6-8 hours), meropenem (1 g every 8 hours), or vancomycin (15-20 mg/kg every 12 hours) plus either aztreonam or a fluoroquinolone for 21 days or longer, as indicated by studies (1). The selection of antibiotics should consider the severity of the infection and the likely causative pathogens, with an emphasis on adjusting the treatment regimen based on culture and sensitivity results to minimize the risk of antibiotic resistance, as highlighted in the 2024 guidelines (1). Key considerations include:
• The use of narrow-spectrum antibiotics for mild infections and broader-spectrum agents for more severe infections.
• The importance of local resistance patterns in guiding antibiotic selection.
• The need for proper wound care and other supportive measures alongside antibiotic therapy.
• The potential for antibiotic resistance and the need to adjust treatment based on culture results. Given the most recent evidence (1), the approach to antibiotic treatment in diabetic foot ulcers should prioritize a tailored regimen based on infection severity and pathogen likelihood, with a strong emphasis on adjusting treatment according to culture results and local resistance patterns to optimize outcomes and minimize resistance.

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 (IV) can be used to treat diabetic foot infections caused by beta-lactamase producing isolates of Staphylococcus aureus 2.

• The usual total daily dosage is 3.375 grams every six hours.
• The usual duration of treatment is from 7 to 10 days.

From the Research

Diabetic Foot Ulcer Antibiotics

• The management of diabetic foot ulcers (DFUs) is crucial to prevent severe physical consequences, such as amputations of limbs, and social, psychological, and economic outcomes 3.
• Infection is a common complication of DFUs, with up to 25% of patients with diabetes developing a DFU in their lifetime, and more than half of them becoming infected 3.
• The diagnosis and treatment of diabetes-related foot infections require consideration of patient risk factors, such as the presence of foot ulcers greater than 2 cm, uncontrolled diabetes mellitus, poor vascular perfusion, and comorbid illness 4.
• Indicators of infection include erythema, induration, tenderness, warmth, and drainage, and deep cultures obtained through aseptic procedures can help guide treatment 4.
• Antibiotic therapy should cover commonly isolated organisms, such as Staphylococcus aureus and Streptococcus agalactiae, and reflect local resistance patterns, patient preference, and the severity of the foot infection 4, 5.
• Mild and moderate infections may be treated with oral antibiotics, while severe infections require intravenous antibiotics, and treatment duration is typically one to two weeks, but may be longer for slowly resolving infections or osteomyelitis 4, 5.
• Empirical antibiotic therapy may increase hospitalization rates, and culture-directed antibiotics are recommended to guide treatment, regardless of DFU infection severity 6.
• Multidisciplinary care, including podiatrists, infectious disease specialists, and vascular surgeons, in close collaboration with primary care clinicians, is associated with lower major amputation rates and improved outcomes 7.

Antibiotic Therapy

• The choice of antibiotic therapy depends on the severity of the infection, with mild and moderate infections typically treated with oral antibiotics, and severe infections requiring intravenous antibiotics 4, 5.
• Culture-directed antibiotics are recommended to guide treatment, as empirical antibiotic therapy may increase hospitalization rates 6.
• The treatment duration is typically one to two weeks, but may be longer for slowly resolving infections or osteomyelitis 4, 5.

Treatment Outcomes

• Diabetic foot ulcers are associated with an increased risk of death, with a 5-year mortality rate of approximately 30%, and exceeding 70% for those with a major amputation 7.
• Multidisciplinary care is associated with lower major amputation rates and improved outcomes, with a significant reduction in hospitalization rates and amputations 7.
• Approximately 30% to 40% of diabetic foot ulcers heal at 12 weeks, and recurrence after healing is estimated to be 42% at 1 year and 65% at 5 years 7.