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Zorluk: OrtaGastroenterology and Hepatology

A 52-year-old man is evaluated in the hospital on day 4 of admission. He originally presented with a 5-day history of high fever, chills, and severe right upper quadrant abdominal pain. His past medical history is notable for poorly controlled type 2 diabetes mellitus. On admission, a CT scan of the abdomen revealed a 6.2-cm solitary, rim-enhancing fluid collection in the right hepatic lobe. He immediately underwent CT-guided percutaneous catheter drainage and was started on empiric intravenous piperacillin-tazobactam.

Today, the patient feels significantly better. His temperature is 37.1°C (98.8°F), blood pressure is 128/82 mmHg, and pulse is 78/min. His leukocyte count has decreased from 21,000/mm³ on admission to 10,500/mm³. The percutaneous drain is outputting a small amount of serosanguinous fluid. Blood cultures from admission show no growth. The abscess fluid culture results have finalized as shown below:

OrganismKlebsiella pneumoniae (Heavy growth)
AmpicillinResistant
CeftriaxoneSusceptible
CiprofloxacinSusceptible
MeropenemSusceptible
Piperacillin-tazobactamSusceptible

Which of the following is the most appropriate next step in the pharmacologic management of this patient?

  1. A
    Continue intravenous piperacillin-tazobactam
  2. B
    Switch to intravenous meropenem
  3. Switch to intravenous ceftriaxoneCevap
  4. D
    Add intravenous vancomycin to the current regimen
  5. E
    Add intravenous fluconazole to the current regimen

Cevap

The most appropriate next step is to switch to intravenous ceftriaxone.
The correct choice represents appropriate antimicrobial de-escalation. The patient has a pyogenic liver abscess that is clinically improving following source control (percutaneous drainage). Initial empiric therapy for a pyogenic liver abscess correctly includes broad-spectrum coverage (e.g., piperacillin-tazobactam) to target enteric Gram-negative bacilli, anaerobes, and Gram-positive organisms. However, once the fluid culture confirms a monomicrobial infection (in this case, Klebsiella pneumoniae) and susceptibilities are finalized, therapy must be de-escalated to a targeted, narrower-spectrum agent to prevent the emergence of multi-drug resistant organisms. Since the isolate is susceptible to ceftriaxone, switching to this third-generation cephalosporin provides optimal, targeted coverage while strictly adhering to antimicrobial stewardship principles.

Adım Adım Çözüm

1
Assess the clinical trajectory and microbiological data.
The patient has a clinically resolving pyogenic liver abscess with finalized cultures showing monomicrobial Klebsiella pneumoniae that is susceptible to multiple agents, including ceftriaxone.
Treatment of liver abscesses must transition from empiric broad-spectrum coverage to targeted therapy once definitive culture data results.
2
Apply principles of antimicrobial stewardship to select the optimal pharmacologic agent.
Ceftriaxone is selected as it is an effective, narrower-spectrum third-generation cephalosporin.
De-escalation to the narrowest effective agent minimizes systemic toxicity, reduces the selection pressure for antimicrobial resistance, and lowers the risk of opportunistic infections.

Anahtar Kavram

Antimicrobial stewardship and therapeutic de-escalation in the management of pyogenic liver abscesses.
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Gastroenterology and Hepatology

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