Empiric Antibiotic Therapy for Gastric Perforation and Peritonitis

Initial Antibiotic Selection

The World Journal of Emergency Surgery recommends piperacillin/tazobactam 4.5g every 6 hours as the first-line therapy for non-critically ill patients due to its activity against gram-positive, gram-negative, and anaerobic bacteria 2, 3
Treatment should be started as soon as possible after peritoneal fluid collection for culture 1
For critically ill patients, piperacillin/tazobactam 4.5g every 6 hours OR cefepime 2g every 8 hours plus metronidazole 500mg every 6 hours is recommended 2, 4
For patients at risk of infection with ESBL-producing Enterobacteriaceae, meropenem 1g every 8 hours is recommended 2

Gastric perforation causes secondary peritonitis, which requires anaerobic coverage in addition to a third-generation cephalosporin 5, 6
Secondary peritonitis from perforation typically shows multiple organisms on Gram stain and culture 6
A short course (3-5 days) of antibiotic therapy is recommended if adequate source control is achieved 1, 3
Continue antibiotics until inflammatory markers normalize 3
Studies show that outcomes after fixed-duration antibiotic therapy were similar to longer courses when adequate source control was achieved 2

Routine antifungal therapy is not recommended for all cases of gastric perforation 3
Antifungal therapy should be reserved for patients who are critically ill and/or severely immunocompromised 3
When indicated, fluconazole can be used in critically ill patients with community-acquired Candida peritonitis without prior azole exposure 2
Echinocandins are recommended as first-line therapy for invasive infections and candidemia in non-neutropenic critically ill patients 2

Healthcare-associated infections, especially in ICU patients or those hospitalized for more than 1 week, increase the risk of multidrug-resistant organisms 3
Corticosteroid use, organ transplantation, baseline pulmonary or hepatic disease also increase the risk of multidrug-resistant organisms 3

If inflammatory markers do not improve, rule out other extra-abdominal sources of infections or different pathogens 3
Consider a de-escalation approach once culture results are available to avoid the development of antimicrobial resistance 3
Modification of the antibiotic regimen should be guided by culture results and clinical status 3

Delayed initiation of antibiotics can increase mortality - start empiric therapy as soon as possible 1
Unnecessary use of broad-spectrum agents for community-acquired infections may contribute to antimicrobial resistance 7