Question

A 34-year-old man with a history of intravenous opioid use disorder is hospitalized for a 1-week history of fever, chills, and pleuritic chest pain. On admission, multiple sets of blood cultures are drawn, and empiric intravenous vancomycin and cefepime are initiated. A transthoracic echocardiogram reveals a $1.4\text{-cm}$ mobile vegetation on the tricuspid valve with moderate tricuspid regurgitation. Two days later, all blood culture bottles grow *Staphylococcus aureus*. Susceptibility testing indicates the isolate is resistant to penicillin G, but susceptible to oxacillin, cefazolin, and vancomycin. The patient's medical record notes a history of a diffuse maculopapular rash after taking amoxicillin for a respiratory infection 5 years ago; he specifically denies any history of facial swelling, difficulty breathing, or anaphylaxis associated with medications. His temperature is currently $37.6^\circ\text{C}$ ($99.7^\circ\text{F}$), blood pressure is $122/76\text{ mm Hg}$, and heart rate is $82/\text{min}$. Which of the following is the most appropriate next step in the pharmacologic management of this patient?