American Society for Microbiology, and the Society of

Infectious Disease Pharmacists, contain evidence-based recommendations for selection of antimicrobial therapy for adult patients with complicated intra-abdominal in-fections. Complicated intra-abdominal infections ex-tend beyond the hollow viscus of origin into the peri-toneal space and are associated either with abscess formation or with peritonitis. These guidelines also ad-dress timing of initiation of antibiotic therapy, when and what to culture, modification of therapy based on culture results, and duration of therapy. Infecting flora. The anticipated infecting flora in these infections and, therefore, the agent(s) selected are determined by whether the infection is community ac-quired or health care associated. Health care–associated intra-abdominal infections are most commonly ac