Severe peritonitis/intra-abdominal abscess

Diagnosis Common Pathogens Drug(s) of First Choice Alternative Drug(s) Comments Expected Duration
(major peritoneal soilage, large or multiple abscesses, patient hemodynamically unstable)

E. coli

Klebsiella

B. fragilis

P. aeruginosa

Enterococcus spp.

Streptococcus spp

S. aureus

Vancomycin

PLUS

Piperacillin/

tazobactam

OR

Meropenem*

For severe PCN allergy:

Vancomycin

PLUS

Aztreonam

PLUS

Metronidazole

*For hemodynamically unstable health-care associated infection, consider meropenem

Fungal coverage rarely needed empirically but consider in high-risk patients: critically ill with upper GI source, recurrent bowel perforation, heavy colonization, surgically-treated pancreatitis

ID consultation is recommended