A 68-year-old man with acute acalculous cholecystitis (confirmed by CT imaging) is critically ill with sepsis, hypotension, and organ dysfunction. He is not a surgical candidate at present. What is the drug of choice for empiric antibiotic coverage?

Explanation

## Antibiotic Management in Acalculous Cholecystitis with Sepsis **Key Point:** Acalculous cholecystitis in critically ill patients requires broader empiric coverage including Pseudomonas aeruginosa and other resistant gram-negative organisms, in addition to standard biliary pathogens. ### Why Piperacillin-Tazobactam is Preferred Piperacillin-tazobactam is a broad-spectrum beta-lactam/beta-lactamase inhibitor that provides: - Excellent coverage of gram-negative aerobes (including Pseudomonas) - Anaerobic coverage via tazobactam - Superior penetration into bile and inflamed tissue - Recommended empiric agent in sepsis with biliary source [cite:Harrison 21e Ch 308] - Single-agent convenience in critically ill patients ### Pathophysiology of Acalculous Cholecystitis in Sepsis Acalculous cholecystitis in ICU patients is often polymicrobial and associated with: 1. Ischemic injury to gallbladder mucosa 2. Secondary bacterial translocation from gut 3. Increased risk of Pseudomonas and other resistant organisms 4. Biliary stasis and inspissated bile **Clinical Pearl:** Acalculous cholecystitis accounts for 5–10% of acute cholecystitis but carries 30% mortality in critically ill patients. Pseudomonas coverage is essential because these patients often have prior antibiotic exposure and ICU-acquired flora. ### Empiric Regimen Comparison in Sepsis | Regimen | Pseudomonas | Anaerobes | Convenience | Renal Dosing | |---|---|---|---|---| | **Piperacillin-tazobactam** | ✓ Excellent | ✓ Excellent | ✓ Single agent | Required | | Ceftriaxone + metronidazole | ✗ No | ✓ Excellent | ✗ Two agents | Minimal | | Amoxicillin-clavulanate + gentamicin | ✓ Moderate | ✗ Poor | ✗ Two agents | Required | | Meropenem monotherapy | ✓ Excellent | ✓ Excellent | ✓ Single agent | Required | **High-Yield:** In **septic/critically ill patients with biliary source**, piperacillin-tazobactam or carbapenems are preferred over cephalosporin combinations because they cover Pseudomonas. In **stable patients with uncomplicated acute cholecystitis**, ceftriaxone + metronidazole suffices.