Question

A male patient, aged $58$, presents to the emergency department complaining of a $3$-day history of fever, chills, and severe left knee swelling. He has a past medical history significant for type $2$ diabetes mellitus but denies any recent falls or joint trauma. Initial vital signs reveal a temperature of $39.1^\circ\text{C}$ ($102.4^\circ\text{F}$), blood pressure of $110/70\text{ mm Hg}$, and heart rate of $112/\text{min}$. Physical examination highlights a warm, intensely erythematous, and exquisitely tender left knee with a noticeable effusion.

Arthrocentesis is performed, yielding frankly purulent synovial fluid with a leukocyte count of $85,000/\text{mm}^3$ ($90\%$ neutrophils). Blood and synovial fluid cultures are obtained, and he is empirically started on intravenous vancomycin and ceftriaxone before undergoing urgent arthroscopic lavage.

On hospital day $3$, the patient demonstrates clinical improvement and is currently afebrile. The microbiology laboratory reports that both the synovial fluid and blood cultures are growing *Staphylococcus aureus*. Susceptibility testing demonstrates that the isolate is resistant to penicillin but susceptible to oxacillin, cefazolin, and clindamycin. The patient's allergy profile notes a mild, non-pruritic maculopapular rash that occurred after taking amoxicillin during childhood; he has never experienced anaphylaxis, angioedema, or respiratory compromise associated with any medication.

Which of the following is the most appropriate antimicrobial regimen for this patient going forward?