What antibiotics are used to treat diabetic foot ulcers (Diabetic Foot Ulcer, DFU)?

From the Guidelines

Antibiotics should only be used in diabetic foot ulcers that show signs of infection, and the choice of antibiotic should be based on the likely causative pathogen(s), clinical severity of the infection, and patient-related factors, with consideration of the most recent guidelines from 2023 1.

Key Considerations

• For mild to moderate infections, oral antibiotics such as amoxicillin-clavulanate, cephalexin, or clindamycin are typically effective for 7-14 days.
• For more severe infections, initial intravenous therapy may be required with agents such as piperacillin-tazobactam, ertapenem, or vancomycin if MRSA is suspected.
• Obtaining wound cultures before starting antibiotics is crucial to guide targeted therapy.
• Antibiotics should be used alongside proper wound care, including debridement of necrotic tissue, pressure offloading, and glucose control.

Choosing the Right Antibiotic

• The choice of antibiotic should consider the likely pathogens (often polymicrobial with Staphylococcus, Streptococcus, and anaerobes) and the depth of infection.
• Beta-lactam antibiotics, metronidazole, clindamycin, linezolid, tetracyclines, trimethoprim-sulfamethoxazole, daptomycin, fluoroquinolones, or vancomycin can be considered, but not tigecycline due to its inferior efficacy compared to ertapenem 1.

Important Notes

• Superficial, uninfected ulcers generally don't require antibiotics, as unnecessary use can lead to resistance.
• Regular reassessment of the wound is essential to determine treatment effectiveness and adjust therapy as needed.
• The 2023 guidelines from the IWGDF/IDSA recommend choosing any of the systemic antibiotic regimens that have shown to be effective in published randomized controlled trials to treat a patient with diabetes and a soft tissue infection of the foot 1.

From the FDA Drug Label

Ertapenem was evaluated in adults for the treatment of diabetic foot infections without concomitant osteomyelitis in a multicenter, randomized, double-blind, non-inferiority clinical trial. This trial compared ertapenem (1 g intravenously once a day) with piperacillin/tazobactam (3. 375 g intravenously every 6 hours). The clinical success rates at 10 days posttherapy were 75.0% (153/204) for ertapenem and 70. 8% (143/202) for piperacillin/tazobactam.

Ertapenem can be used as an antibiotic for the treatment of diabetic foot infections without concomitant osteomyelitis, with a clinical success rate of 75.0% at 10 days posttherapy 2.

From the Research

Antibiotics for Diabetic Foot Ulcer

• The use of antibiotics in treating diabetic foot ulcers is a crucial aspect of management, as these ulcers are prone to infection 3, 4, 5, 6.
• Studies have shown that foot infections in diabetic patients are predominantly caused by gram-positive cocci, but there is also a significant presence of gram-negative isolates 3, 4.
• The choice of antibiotic should be guided by the microbial profile of the infection, as well as local resistance patterns and patient-specific factors 4, 6.
• Linezolid has been shown to be effective in treating foot infections in diabetic patients, particularly those with infected foot ulcers and without osteomyelitis 3.
• Other antibiotics such as vancomycin, ampicillin-sulbactam, and amoxicillin-clavulanate have also been used to treat diabetic foot ulcers, but the choice of antibiotic should be tailored to the individual patient's needs 4, 5, 6.
• The duration of antibiotic treatment typically ranges from one to two weeks, but may be longer for slowly resolving infections or osteomyelitis 6.
• It is essential to note that antibiotic treatment should be part of a comprehensive management plan that includes wound care, offloading, and glucose control 5, 6, 7.

Microbial Profile and Antibiotic Treatment

• The microbial profile of diabetic foot ulcers can vary, with both gram-positive and gram-negative isolates present 3, 4.
• Polymicrobial infections are common, and the choice of antibiotic should reflect this 4, 6.
• The use of broad-spectrum antibiotics such as vancomycin and Zosyn may increase the risk of antibiotic-induced nephrotoxicity 4.
• Alternative antibiotics with broad-spectrum coverage and minimal nephrotoxicity, such as ceftriaxone, clindamycin, metronidazole, amoxicillin-clavulanate, and linezolid, should be considered 4.

Treatment Outcomes and Management

• The treatment of diabetic foot ulcers requires a multidisciplinary approach, including wound care, offloading, and glucose control 5, 6, 7.
• Early antibiotic treatment may be beneficial for patients with clean ulcers associated with peripheral vascular disease and positive ulcer swabs 5.
• The use of adjunctive therapies such as negative pressure wound therapy, skin substitutes, and platelet-derived growth factor may be beneficial, but the evidence is limited 7.
• Regular assessment and counseling are essential for preventing and managing diabetic foot ulcers 6.