A 72-year-old man undergoes one-stage exchange arthroplasty for a culture-negative periprosthetic joint infection after total knee replacement. Intraoperative cultures show no growth. Which antibiotic regimen is most appropriate for the post-operative period?

• A No antibiotics since cultures are negative
• B Broad-spectrum IV antibiotics for 2 weeks, then oral suppression
• C Empiric IV vancomycin plus a third-generation cephalosporin for 4 to 6 weeks ✓
• D Oral rifampicin alone for 6 weeks

Explanation

Culture-negative PJI still requires full-course empiric IV antibiotic therapy targeting the most common organisms (Staphylococcus aureus, coagulase-negative staphylococci). Standard practice is 4 to 6 weeks of IV antibiotics, typically vancomycin plus a cephalosporin or beta-lactam. Culture negativity does not rule out infection.

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

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Written and medically reviewed by the StethoPrep medical team.