Will cephalexin (cephalexin) provide adequate coverage for a mild superficial wound infection with gram-positive cocci in pairs, suspected to be resistant?

Cephalexin for Gram-Positive Cocci in Pairs in a Superficial Wound Infection

Cephalexin is an appropriate antibiotic choice for treating a mild superficial wound infection with gram-positive cocci in pairs, assuming no resistance is present. 1

Rationale for Cephalexin Use

Cephalexin is specifically indicated for skin and skin structure infections caused by Staphylococcus aureus and Streptococcus species 1. The FDA label confirms that cephalexin is active against most strains of these gram-positive organisms, which are the most likely pathogens when gram-positive cocci in pairs are identified in a wound culture.

The Infectious Diseases Society of America (IDSA) guidelines support using cephalexin as a first-line agent for mild skin and soft tissue infections:

• For mild-to-moderate infections in patients who have not recently received antibiotic therapy, therapy aimed at aerobic gram-positive cocci (such as cephalexin) is sufficient 2
• Cephalexin is specifically listed as a first-choice antibiotic for skin and soft tissue infections by the WHO Essential Medicines list 2

Dosing and Duration

• For mild superficial infections: 500 mg orally four times daily for 5-10 days
• Adjust dosing in patients with renal impairment
• Duration of therapy for mild skin infections is typically 5-10 days 3

Efficacy and Coverage

Cephalexin has demonstrated excellent efficacy against susceptible strains of:

• Staphylococcus aureus (including penicillinase-producing strains)
• Streptococcus species 1

Historical data shows cure rates of 90% or higher for streptococcal and staphylococcal skin infections with cephalexin 4.

Important Limitations and Considerations

1. MRSA coverage: Cephalexin does not cover methicillin-resistant Staphylococcus aureus (MRSA) 1

   • If MRSA is suspected or confirmed, alternative therapy with clindamycin, trimethoprim-sulfamethoxazole, or doxycycline would be appropriate 3

2. Recent antibiotic exposure: If the patient has recently received antibiotics, consider broader coverage due to increased risk of resistant organisms 2

3. Drainage: For any abscess component, incision and drainage is the primary treatment, with antibiotics as adjunctive therapy 2

4. Follow-up: Reassess within 48-72 hours to ensure clinical improvement 2

When to Consider Alternative Therapy

Consider switching from cephalexin if:

• No clinical improvement after 48-72 hours
• Culture results show resistance to cephalexin
• MRSA is identified in culture
• Patient develops systemic symptoms suggesting more severe infection

Bottom Line

For a mild superficial wound infection with gram-positive cocci in pairs and no known resistance, cephalexin is an appropriate first-line antibiotic choice with excellent efficacy. Close follow-up within 48-72 hours is essential to ensure clinical improvement and adjust therapy if needed based on culture results.