A 72-year-old woman is admitted to the intensive care unit with a temperature of 39.2°C (102.6°F), severe right upper quadrant abdominal pain, and new-onset confusion. Her blood pressure is 88/54 mmHg, and her heart rate is 112/min. Physical examination is notable for marked scleral icterus and right upper quadrant tenderness with guarding.
| Test | Result |
|---|---|
| Leukocyte count | 18,500/mm³ |
| Total bilirubin | 6.8 mg/dL |
| Direct bilirubin | 5.2 mg/dL |
| Alkaline phosphatase | 510 U/L |
| Aspartate aminotransferase (AST) | 145 U/L |
| Alanine aminotransferase (ALT) | 160 U/L |
A bedside ultrasound shows a dilated common bile duct of 14 mm and an obstructive echogenic stone. She receives aggressive intravenous fluid resuscitation and is empirically started on broad-spectrum coverage with intravenous piperacillin-tazobactam. An emergent endoscopic retrograde cholangiopancreatography (ERCP) is performed, which successfully extracts the stone and drains purulent bile.
On hospital day 3, the patient is hemodynamically stable, alert, and afebrile. She is tolerating an oral diet. Blood cultures obtained at admission return positive for a single organism. The susceptibility report is as follows:
| Organism: *Klebsiella pneumoniae* | |
|---|---|
| Ampicillin | Resistant |
| Ceftriaxone | Susceptible |
| Ciprofloxacin | Susceptible |
| Piperacillin-tazobactam | Susceptible |
Which of the following is the most appropriate next step in the pharmacologic management of this patient?
- De-escalate antimicrobial therapy to intravenous ceftriaxoneAnswer
- BContinue the current regimen of intravenous piperacillin-tazobactam
- CAdd intravenous metronidazole to provide comprehensive anaerobic coverage
- DTransition therapy to oral rifaximin for outpatient management
- EDiscontinue all antimicrobial therapy immediately