The aim of the project is to perform a multinational, prospective, observational study on IAIs (IntraAbdominal Infections) in critically ill patients; special emphasis will be given to epidemiology and outcomes.

To investigate microbiology and/or drug resistance patterns related to: Geographical region, Source of IAI, Upper GI tract perforation (stomach & duodenum), Lower GI tract perforation (jejunum, ileum, colon, rectum), Primary peritonitis, Peritoneal dialysis-related peritonitis, Intra-abdominal abscess, Pancreatic infection, Biliary tract infection, Typhlitis, Toxic megacolon.

To check the Origin of IAI: community-acquired, early-onset healthcare-associated, late-onset healthcare-associated.

To describe physician's antimicrobial prescription patterns related to a classification grid that stratifies IAIs according to disease expression, community or healthcare origin, and anatomical disruption.

To investigate outcomes (clinical response, need for surgical revision, length of hospitalization, and mortality) related to: Classification of IAI, Severity of acute illness at time of diagnosis (SOFA score) and clinical response after 48-72 hrs. (SOFA score), Processes of care (Time to 1st antimicrobial dose, Time to source control, Type of source control intervention (laparotomy, percutaneous drainage, high volume peritoneal lavage, restoration of anatomy and function), Need for (unplanned) surgical revision (uncontrolled infection source), Frequency of microbiological sampling and delay of results)), Pathogens involved and empirical antimicrobial coverage; special emphasis will be given, to coverage of multidrug resistant Enterobacteriaceae, Pseudomonas aeruginosa, enterococci and Candida species, Duration of antimicrobial therapy, Underlying conditions

Inclusion Criteria:

• Adult (≥18 yrs. of age)
• IAI treated with percutaneous or surgical procedure
• ICU admission (the patient should either be admitted to the ICU because of abdominal sepsis or should be admitted in the ICU for other reasons and subsequently developed abdominal sepsis as a complication during the ICU course)
• Informed consent (if required by local ethics committee)

Exclusion Criteria:

<18 yrs

All consecutive, adult ICU patients diagnosed with IAI- intra-abdominal infection (either as a primary diagnosis or as a complication during the ICU course) during a 6 months period and with a maximum of 15 cases per unit.