Soru

A medical team is rounding on a $59$-year-old man admitted $3$ days ago with fever, abdominal pain, and confusion. He has a known history of decompensated cirrhosis due to chronic hepatitis C. At the time of admission, an emergency diagnostic paracentesis yielded cloudy fluid with an absolute neutrophil count of $850/\text{mm}^3$, confirming spontaneous bacterial peritonitis. Because he had been hospitalized $4$ weeks prior for a variceal bleed, the inpatient team initiated empiric therapy with intravenous piperacillin-tazobactam to cover potential healthcare-associated pathogens.

Currently, the patient is clinically stable. His confusion has cleared, and he reports no abdominal pain. Vital signs today show a temperature of $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), blood pressure of $112/70\,\text{mmHg}$, and a heart rate of $78/\text{min}$. The microbiology laboratory reports that the admission ascitic fluid culture is positive for *Escherichia coli*. Antimicrobial susceptibility testing demonstrates that the isolate is sensitive to ceftriaxone, cefotaxime, and ciprofloxacin, but resistant to ampicillin.

Which of the following is the most appropriate next step in pharmacotherapy?