A 62-year-old woman is evaluated on hospital day 3. She initially presented with fever, severe right upper quadrant pain, and jaundice. She was diagnosed with acute ascending cholangitis. On admission, she was started on empiric intravenous piperacillin-tazobactam and subsequently underwent urgent endoscopic retrograde cholangiopancreatography (ERCP) with successful sphincterotomy and stone extraction. Her symptoms have now resolved, and she has been afebrile for 48 hours. Vital signs are within normal limits. Blood cultures drawn at admission are now positive for *Escherichia coli*. The susceptibility report is shown below:
| Antimicrobial | Interpretation |
|---|---|
| Ampicillin | Resistant |
| Ceftriaxone | Susceptible |
| Ciprofloxacin | Susceptible |
| Piperacillin-tazobactam | Susceptible |
| Meropenem | Susceptible |
Which of the following is the most appropriate next step in the pharmacologic management of this patient?
- Switch to intravenous ceftriaxoneAnswer
- BContinue intravenous piperacillin-tazobactam
- CSwitch to intravenous meropenem
- DAdd intravenous vancomycin
- ESwitch to intravenous ampicillin
Answer
Switch to intravenous ceftriaxone
The patient developed acute ascending cholangitis and has now achieved source control through an ERCP with sphincterotomy. Her blood cultures have isolated *Escherichia coli* that is susceptible to ceftriaxone. According to the core principles of antimicrobial stewardship, once culture and susceptibility data become available, an empiric broad-spectrum antibiotic regimen (such as piperacillin-tazobactam) should be promptly de-escalated to a targeted, narrower-spectrum agent. Ceftriaxone provides excellent, targeted coverage for this specific *E. coli* isolate, minimizing collateral damage to the patient's normal flora and reducing the risk of antibiotic resistance.
Step-by-Step Solution
Key Concept
Antimicrobial Stewardship in Biliary Infections
Estimated Time:1m 15s