What is the best antibiotic (abx) for a foot skin infection?

From the Guidelines

For a foot skin infection, the best antibiotic treatment is cephalexin 500 mg orally four times daily for 7-10 days, as it effectively covers Staphylococcus aureus and Streptococcus species, the most common causes of skin infections, as recommended by the Infectious Diseases Society of America 1.

Key Considerations

• The choice of antibiotic should target the most likely pathogens while considering local resistance patterns and individual patient factors like allergies and comorbidities.
• If MRSA is suspected, consider alternative antibiotics such as clindamycin, trimethoprim-sulfamethoxazole, or doxycycline.
• For diabetic patients or those with compromised circulation, broader coverage may be necessary with amoxicillin-clavulanate.
• Keep the foot clean, elevated when possible, and monitor for signs of worsening infection.

Antibiotic Options

• Cephalexin: 500 mg orally four times daily for 7-10 days
• Clindamycin: 300-450 mg orally three times daily
• Trimethoprim-sulfamethoxazole: 1-2 double-strength tablets twice daily
• Doxycycline: 100 mg twice daily
• Amoxicillin-clavulanate: 875/125 mg twice daily

Important Notes

• Incision and drainage may be necessary for abscesses or furuncles, and antibiotic therapy may be recommended after drainage 1.
• The Infectious Diseases Society of America recommends selecting an empiric antibiotic regimen based on the severity of the infection and the likely etiologic agent(s) 1.
• The IDSA also suggests basing the route of therapy largely on infection severity, with parenteral therapy preferred for severe infections and oral agents for mild to moderate infections 1.

From the FDA Drug Label

For the following infections, a dosage of 500 mg may be administered every 12 hours: streptococcal pharyngitis, skin and skin structure infections, and uncomplicated cystitis in patients over 15 years of age. The best antibiotic for a foot skin infection is cephalexin 2.

• The recommended dose is 500 mg every 12 hours.
• It is essential to note that the treatment should be based on the severity of the infection and the susceptibility of the causative organism.

From the Research

Antibiotic Options for Foot Skin Infections

The choice of antibiotic for a foot skin infection depends on the causative pathogen and its susceptibility to various antibiotics.

• For community-acquired meticillin-resistant Staphylococcus aureus (MRSA) skin and soft-tissue infections, minocycline is a preferred option 3.
• Cefdinir has been shown to be effective in treating skin and skin-structure infections, with a high rate of pathogen eradication and successful clinical response 4.
• For impetigo, topical antibiotics such as mupirocin, retapamulin, and fusidic acid are recommended, while oral antibiotic therapy can be used for large bullae or when topical therapy is impractical 5.
• Gram-negative bacterial toe web infections can be successfully treated with a third-generation cephalosporin such as cefoperazone 6.
• In patients with atopic dermatitis, cephalexin appears to be a preferential first-line antibiotic for the treatment of bacterial superinfections with S. aureus due to its restricted antimicrobial spectrum 7.

Considerations for Antibiotic Resistance

• The increasing prevalence of antibiotic-resistant bacteria, including MRSA, macrolide-resistant streptococcus, and mupirocin-resistant streptococcus, should be considered when selecting an antibiotic 3, 5, 7.
• Antimicrobial susceptibility testing is essential to determine the effectiveness of various antibiotics against specific pathogens 7.
• The choice of antibiotic should be based on the suspected or confirmed causative pathogen and its susceptibility to various antibiotics 3, 4, 5, 6, 7.