Impact of Rapid Molecular Diagnostic Method on Antibiotics Exposure Duration in ICU Patients with Postoperative Peritonitis

Hospitals, and more specifically Intensive Care Units (ICU), face the challenging issue of emergence and rapid spread of multi-drug resistant bacteria (MDR). In some cases, the therapeutic choice is extremely limited. Prevention and adequacy of antibiotic therapy (AB) are the key responses applied toward these threats. A delayed adequate AB is a known factor of poor prognosis. Intra-abdominal infections (IAI) are frequent, polymicrobial and life threatening diseases. Source control and adequate AB are instrumental issues in this setting. Despite technical advances, susceptibility testing of the microorganisms collected from peritoneal samples is not usually available before day two or three after surgery. In this time lapse, empiric AB might be inadequate (not targeting all the pathogens, which leads to a prolonged duration of AB and potential increased morbidity/mortality risk) or too broad (with the two issues of ecology with an increased risk of selection of MDR bacteria and additional costs). In a pilot study evaluating the potential benefit of a direct culture of peritoneal samples from resuscitation patients treated for peritonitis, we observed that conventional treatment made it possible to obtain microbiological results within a median of 3 \[extremes 2-7\] days whereas a direct microbiological technique by E-test gave results in 1 \[1-2\] days (p \<0.0001). With this technique close to conventional microbiological, a change in antibiotic therapy could have been achieved within an average of 1 \[1-2\] days versus 4 \[1-11\] days with conventional management (p = 0, 0006). The development of modern molecular techniques suggests that a large margin of improvement for the rendering and the precision of the results is possible.