A 35-year-old intravenous drug user presents with 2 weeks of high fever, new murmur, and multiple septic pulmonary emboli on CT chest. Blood cultures grow Staphylococcus aureus. Echocardiography confirms a 1.5 cm vegetation on the tricuspid valve with severe TR. He has no left-sided valve involvement. What is the recommended antibiotic regimen duration for right-sided S. aureus endocarditis in PWID?

• A IV vancomycin or anti-staphylococcal penicillin for 4–6 weeks
• B Oral amoxicillin-clavulanate for 6 weeks after initial 1-week IV therapy
• C IV ceftriaxone for 4 weeks
• D IV vancomycin for 2 weeks only — right-sided IE in PWID can be treated with a shorter 2-week course if no complications ✓

Explanation

A key point from IE guidelines (AHA/ESC) is that uncomplicated right-sided S. aureus endocarditis in people who inject drugs (PWID) can be effectively treated with just 2 weeks of IV antibiotics (cloxacillin/nafcillin for MSSA, or vancomycin for MRSA), provided there is no left-sided involvement, no embolic complications, no perivalvular extension, and rapid clinical response. Longer courses (4–6 weeks) are required for complicated or left-sided disease. This shorter regimen facilitates addiction treatment and reduces prolonged IV access risks.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

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Written and medically reviewed by the StethoPrep medical team.