What is the appropriate antibiotic choice for an infected heel ulcer?

From the Guidelines

For an infected heel ulcer, empiric antibiotic therapy should initially cover both gram-positive and gram-negative organisms, with consideration for methicillin-resistant Staphylococcus aureus (MRSA) depending on risk factors, and a reasonable first-line regimen would be amoxicillin-clavulanate 875/125 mg orally twice daily for 7-10 days, as suggested by the most recent guidelines 1.

Key Considerations

• The choice of antibiotic should be guided by the severity of the infection and the likely etiologic agent(s) 1.
• For mild to moderate infections, therapy targeting aerobic gram-positive cocci (GPC) may be sufficient, but for severe infections, broad-spectrum empiric antibiotic therapy is recommended, pending culture results and antibiotic susceptibility data 1.
• The route of therapy should be based largely on infection severity, with parenteral therapy preferred for severe and some moderate infections, at least initially, and a switch to oral agents when the patient is systemically well and culture results are available 1.

Antibiotic Options

• For patients with penicillin allergy, clindamycin 300-450 mg orally four times daily is an alternative 1.
• If MRSA is suspected or the infection appears more severe, consider trimethoprim-sulfamethoxazole (TMP-SMX) 1-2 double-strength tablets twice daily, possibly combined with cephalexin 500 mg four times daily for broader coverage 1.
• For moderate to severe infections requiring hospitalization, intravenous options include vancomycin 15-20 mg/kg every 12 hours plus either piperacillin-tazobactam 4.5 g every 6-8 hours or cefepime 2 g every 8-12 hours 1.

Wound Care

• Beyond antibiotics, proper wound care is essential, including regular debridement of necrotic tissue, offloading pressure from the heel, and maintaining a moist wound environment 1.
• Diabetic patients require particularly close monitoring and may need longer treatment courses 1.

Duration of Therapy

• The duration of antibiotic therapy can generally be discontinued when the signs of infection have resolved, but not before, and the optimal durations are usually 1-2 weeks for mild to moderate skin and soft tissue infections and 3 weeks for more serious infections 1.

From the FDA Drug Label

Adult diabetic patients with clinically documented complicated skin and skin structure infections ("diabetic foot infections") were enrolled in a randomized (2:1 ratio), multi-center, open-label trial comparing study medications administered IV or orally for a total of 14 to 28 days of treatment The cure rates in the ITT population were 68.5% (165/241) in linezolid-treated patients and 64% (77/120) in comparator-treated patients, where those with indeterminate and missing outcomes were considered failures. The cure rates by pathogen for microbiologically evaluable patients are presented in Table 19. Table 19 Cure Rates at the Test-of-Cure Visit for Microbiologically Evaluable Adult Patients with Diabetic Foot Infections Pathogen Cured ZYVOXn/N (%) Comparatorn/N (%) Staphylococcus aureus 49/63 (78) 20/29 (69) Methicillin-resistant S aureus 12/17 (71) 2/3 (67) Streptococcus agalactiae 25/29 (86) 9/16 (56)

Antibiotic choice for an infected heel ulcer:

• Linezolid may be considered as a treatment option, with cure rates of 78% for Staphylococcus aureus and 71% for Methicillin-resistant S aureus in diabetic foot infections 2.
• Daptomycin may also be considered, with clinical success rates of 86% for Methicillin-susceptible Staphylococcus aureus and 75% for Methicillin-resistant Staphylococcus aureus in complicated skin and skin structure infections 3.
• However, the choice of antibiotic should be based on the specific pathogen and local resistance patterns.
• It is essential to note that these studies were not specifically conducted on heel ulcers, but rather on complicated skin and skin structure infections or diabetic foot infections.
• Therefore, the results should be applied with caution to the treatment of infected heel ulcers.

From the Research

Antibiotic Choice for Infected Heel Ulcer

• The choice of antibiotic for an infected heel ulcer depends on several factors, including the severity of the infection, the presence of underlying conditions such as diabetes, and the suspected or confirmed causative pathogens 4.
• For moderate to severe diabetic foot infections, piperacillin/tazobactam and ampicillin/sulbactam have been shown to be effective treatments, with similar clinical efficacy rates and median duration of treatment 5.
• Piperacillin/tazobactam has the advantage of covering Pseudomonas aeruginosa, a common gram-negative pathogen in diabetic foot infections 5.
• The selection of antibiotic therapy should be guided by clinical clues, such as the severity of the infection, the presence of aerobic Gram-positive cocci, and the need for coverage of aerobic Gram-negative pathogens and anaerobes 4.
• In critically ill patients, the administration of antibiotics should be optimized to ensure optimal drug delivery to the site of infection, taking into account factors such as dosing, interval of administration, and route of administration 6.

Key Considerations

• The broad spectrum of antibacterial activity of piperacillin/tazobactam makes it a useful option for the treatment of polymicrobial infections caused by aerobic or anaerobic beta-lactamase-producing bacteria 7.
• The combination of piperacillin/tazobactam with an aminoglycoside may be used to treat severe nosocomial infections, and has been shown to be effective in the treatment of febrile neutropenia 7.
• The treatment of diabetic foot infections should be individualized, taking into account the severity of the infection, the presence of underlying conditions, and the suspected or confirmed causative pathogens 5, 4.