Secondary peritonitis

• abscess
• bowel perforation
• ruptured appendix

- Drainage and debridement essential.

- Cultures of perforated or gangrenous appendix offer no benefit. However, distal colonic perforations warrant aerobic/anaerobic cultures as antibiotic therapy should be tailored to C&S results.

- Duration of therapy:

Peri-operative therapy ≤ 24h:

• Bowel injuries due to penetrating, blunt, or iatrogenic trauma with surgery within 12 hours of injury; acute perforations of stomach, duodenum, and proximal jejunum in absence of antacid therapy or malignancy; or acute appendicitis without gangrene, perforation, abscess, or peritonitis.

Short course (5-7 days):

• Uncomplicated peritonitis if adequate drainage.

• Persistent clinical evidence of infection after 5-7 days warrants diagnostic investigations (CT, US).

Prolonged course:

• Complicated intraabdominal abscesses and/or severe underlying illness.

• Continue therapy until:

  • afebrile

  • normal WBC/differential

  • no residual fluid collections

  • return of GI function.

Usual Pathogens

Polymicrobial:

Enterobacteriaceae
Enterococcus spp
Anaerobes
Streptococcus spp
Candida spp

Mild-moderate

Severe ß-lactam allergy

Enterococcal coverage required

Severe/ICU

Multiple previous antibiotics/known ESBL or AmpC

Oral switch therapy

- Switch to oral agents when tolerating oral intake and clinical improvement.

Severe ß-lactam allergy