Soru

A 64-year-old female patient is currently hospitalized for the treatment of acute pyelonephritis. She initially presented to the emergency department three days ago with severe right-sided flank pain, dysuria, and a temperature of $39.2^\circ\text{C}$ ($102.6^\circ\text{F}$). Blood cultures were drawn, and empiric intravenous ceftriaxone was initiated. The admission blood cultures show no growth to date. However, the urine culture obtained prior to antibiotic administration has grown $>10^5$ colony-forming units/mL of *Escherichia coli*. The susceptibility report is as follows:

Today, the patient reports that her flank pain has nearly resolved. Her current temperature is $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), blood pressure is $122/78 \text{ mmHg}$, and heart rate is $78/\text{min}$. She is tolerating a regular diet without nausea.

Based on the culture results and the patient's clinical progress, which of the following is the most appropriate next step in the pharmacologic management of this patient?