What is the most appropriate oral antibiotic regimen for a patient with a purulent skin abscess due to methicillin-susceptible Staphylococcus aureus (MSSA) at the time of discharge?

Oral Antibiotic Regimen for MSSA Skin Abscess After IV Treatment

Clindamycin 600 mg orally every 8 hours is the most appropriate oral antibiotic regimen for JJ at discharge for treatment of her MSSA skin abscess. 1

Rationale for Clindamycin Selection

Clindamycin is specifically recommended by the Infectious Diseases Society of America (IDSA) guidelines for skin and soft tissue infections at a dose of 600 mg every 8 hours. It offers excellent tissue penetration for skin infections, which is crucial for treating abscesses effectively 1.

For methicillin-susceptible Staphylococcus aureus (MSSA) infections like JJ's case, the following considerations support clindamycin as the optimal choice:

• Clindamycin provides good coverage against MSSA and has excellent tissue penetration for skin and soft tissue infections 1
• The recommended dosage of 600 mg every 8 hours aligns with established guidelines for treating skin infections 1
• JJ has already had surgical drainage of her abscess and has completed 9 days of IV antibiotics with documented clinical improvement, making her suitable for oral step-down therapy

Analysis of Alternative Options

1. Sulfamethoxazole/trimethoprim (TMP-SMX)

   • While TMP-SMX is effective for community-acquired MRSA, it is not the first-line choice for confirmed MSSA infections 1
   • The typical dosage would be 1-2 double-strength tablets (160mg/800mg) twice daily, not the 400mg/80mg dose listed in the options 1

2. Oral Vancomycin

   • Oral vancomycin has poor systemic absorption and is primarily used for Clostridioides difficile infections
   • It would not be appropriate for treating a systemic MSSA infection 1

3. Linezolid

   • While linezolid is effective against MSSA, it is typically reserved for more severe infections or treatment failures 1, 2
   • It is considerably more expensive than clindamycin and has more potential adverse effects with prolonged use
   • Guidelines recommend reserving linezolid for patients who fail on or are intolerant of conventional therapy 2

Important Clinical Considerations

• Duration of therapy: The IDSA guidelines recommend a 5-10 day course of antibiotics for uncomplicated skin and soft tissue infections 1
• JJ has already received 9 days of IV antibiotics, so a shorter course of oral therapy may be appropriate to complete treatment

Potential Pitfalls to Avoid

• Inadequate duration of therapy: Ensure JJ completes the full prescribed course of antibiotics even if symptoms improve quickly to prevent recurrence 1
• Clindamycin resistance: Although not mentioned in this case, it's important to verify susceptibility to clindamycin when treating S. aureus infections, as inducible resistance can occur 3
• Monitoring for adverse effects: Educate JJ about potential side effects of clindamycin, particularly gastrointestinal symptoms and the rare but serious risk of Clostridioides difficile infection

Patient Education Points

• Take medication with food to minimize gastrointestinal side effects
• Complete the entire course of antibiotics even if symptoms improve
• Return for follow-up if symptoms worsen or do not continue to improve
• Maintain proper wound care and hygiene to prevent recurrence

By selecting clindamycin 600 mg orally every 8 hours, JJ will receive appropriate coverage for her MSSA infection while following evidence-based guidelines for skin and soft tissue infections.