Choosing wisely: what's the actual role of antimicrobial stewardship in intensive care units?

More than two-thirds of critically ill patients receive an antimicrobial therapy with a percentage between 30 and 50% of all prescribed antibiotics reported to be unnecessary, inappropriate or misused. Since inappropriate prescription of antibiotic drugs concurs to dissemination of the multi-drug resistant organisms, a reasoned antibiotics use is crucial especially in Intensive Care Unit (ICU), where up to 60% of the admitted patients develops an infection during their ICU stay. Even if the concept of Antimicrobial Stewardship (AS) has been clearly described as a series of coordinated interventions designed to improve antimicrobial agents use, few studies are reporting about its effectiveness to improve outcomes, reduce adverse events and costs and decrease resistance rate spread. Moreover, although it is recognized that AS programs are particularly indicated in the critical setting due to the huge number of antimicrobial drugs used, the optimal characteristics of these interventions and the best system to evaluate their effectiveness are still unclear. Specific interventions, designed tacking into account the peculiarities of the ICU setting, are hence necessary to set-up an 'in-ICU-stewardship', including prompt identification of infected patients, selection of appropriate empiric treatments, optimization of dosing and route of administration, improvement of diagnostic techniques, early de-escalation to achieve shorter duration and avoid unnecessary therapies. The present narrative review summarizes the "state of art" about AS programmes and discusses the effects of the interventions possibly applied in ICU setting to optimize the patient's treatment, reduce the micro-organisms resistance and contain the hospital resources utilization.