Tertiary Peritonitis

Persistent or recurrent nosocomial infection of the peritoneal cavity following an episode of apparently treated secondary peritonitis

Diagnostic Pearls

Prompt abdominal and pelvic CT to identify source

Surgical/gastroenterology consultation for source control, (debridement, percutaneous drainage), which is the cornerstone of therapy

Blood cultures in severely ill and health care associated complicated infections; peritoneal cultures can help define microbiology

Procalcitonin (PCT) not usually useful

Duration of Therapy

Usually long (i.e. weeks)

ID consult recommended
Microbiology may be dynamic and alter both antibiotic options and duration
Oral step-down with potent therapy may be eventually possible in clinically and microbiologically stable cases

If previously on Ceftriaxone:

Piperacillin/Tazobactam 4.5g IV Q6H

AND

Vancomycin 25mg/kg LOAD then according to Vancomycin Nomogram

ALTERNATIVELY

If previously on Piperacillin/Tazobactam or Critically Ill:

Meropenem 1g IV Q8H

AND

Vancomycin 25mg/kg LOAD then according to Vancomycin Nomogram

If Candida present from peritoneal cultures

ADD

Fluconazole 400mg PO/IV Q24H

OR, for non-albicans species (e.g. glabrata)

Micafungin 100mg IV Q24H

Usual Organisms (can be polymicrobial)

Enterobacteriaceae (E. coli, Klebsiella)

ESBLs

Enterococcus faecalis

Candida

Organisms of Interest in IAI