Is fixed short-course antimicrobial therapy justified for patients who are critically ill with intra-abdominal infections?

A long-course antibiotic therapy increases the risk of antibiotic resistance. A 7- to 14-day duration of therapy has been traditionally adopted in patients with intra-abdominal infections (IAIs). Prophylactic antibiotic use is warranted in uncomplicated IAIs, in which the infection involves a single organ, and the source of the infection is completely eradicated by a surgical procedure. A large, randomized clinical trial of the treatment of complicated IAIs recently demonstrated that a fixed 4-day course of antibiotic therapy was as effective as a long-course therapy in patients who underwent adequate source control. Considering the poor prognosis and lack of clear evidence available for shortening the duration of antibiotic therapy in patients who are critically ill or those with ongoing signs of sepsis, the duration of therapy for complicated IAIs should be individually determined according to the clinical course. Limiting therapy to no more than 7 days seems to be warranted in patients who are critically ill with a good clinical response.