A 60-year-old diabetic with peripheral vascular disease develops chronic osteomyelitis of the calcaneum with a discharging sinus. Bone biopsy and culture grow methicillin-resistant Staphylococcus aureus (MRSA). The antibiotic of choice for MRSA osteomyelitis requiring prolonged oral therapy after initial IV treatment is:
- A Amoxicillin-clavulanate
- B Vancomycin (oral form only)
- C Linezolid (oral bioavailability 100%) ✓
- D Meropenem
Explanation
MRSA osteomyelitis requires anti-MRSA agents. Linezolid has excellent oral bioavailability (~100%), allowing seamless IV-to-oral step-down, achieves good bone concentrations, and is active against MRSA. It is used for chronic osteomyelitis where prolonged oral therapy is needed. Oral vancomycin is not absorbed and only used for C. difficile colitis (IV vancomycin is used for MRSA). Amoxicillin-clavulanate and meropenem have no anti-MRSA activity. Other oral MRSA options include trimethoprim-sulfamethoxazole + rifampicin for chronic biofilm MRSA osteomyelitis. Monitoring for linezolid toxicity (thrombocytopenia, neuropathy) is required beyond 2 weeks.
Reference: Maheshwari Essential Orthopaedics, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.