Question

An elderly male patient, aged 72, comes to the clinic reporting a four-week history of profound fatigue, night sweats, and unintentional weight loss. He notes that these symptoms began roughly two weeks after he underwent a transurethral resection of the prostate for benign prostatic hyperplasia. His temperature in the clinic is 38.2°C (100.8°F), blood pressure is 134/68 mm Hg, and pulse is 96/min. Cardiovascular auscultation reveals a new early diastolic decrescendo murmur best heard at the left third intercostal space. Physical examination also demonstrates nontender, erythematous macules on the palms and soles. Transesophageal echocardiography confirms a mobile, 1.1-cm vegetation on the right coronary cusp of the aortic valve. Two days later, all three sets of blood cultures are positive for *Enterococcus faecalis*. Antimicrobial susceptibility testing indicates that the isolate is susceptible to ampicillin and vancomycin. However, high-level resistance to both gentamicin and streptomycin is detected. Renal function is within normal limits. Which of the following is the most appropriate definitive intravenous antibiotic regimen for this patient?