Impact of a mixed educational and semi-restrictive antimicrobial stewardship project in a large teaching hospital in Northern Italy

Background: The overuse of antimicrobials favors the dissemination of antimicrobialresistance, as well as invasive fungal diseases and Clostridium difficile infections (CDI). In this study, we assessed the impact of a mixed educational and semi-restrictive antimicrobial stewardship (AMS) project in a large teaching hospital in Italy. Methods: The AMS project was conducted from May 2014 to April 2016. It consisted of two initiatives in two consecutive periods: (1) educational activities; (2) semi-restrictive control of antimicrobial prescribing through a computerized software. The primary endpoint was consumption of antibacterials and antifungals. Secondary endpoints were incidence of CDI, methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infections (BSI), carbapenem-resistant Klebsiella pneumoniae (CRKP) BSI, and Candida BSI. Results: During the study period, a statistically significant reduction in consumption was observed for antibacterials (−1.45 defined daily doses (DDD)/1000 patient-days monthly, 95% confidence intervals [CI] −2.38 to −0.52, p 0.004), mainly driven by reductions in the use of fluoroquinolones, third/fourth generation cephalosporins, and carbapenems. No decrease in consumption of antifungals was observed (−0.04 DDD/1000 patient-days monthly, 95% CI −0.34 to +0.25, p 0.750). A statistically significant trend towards reduction was observed for incidence of CRKP BSI (incidence rate ratio 0.96, 95% CI 0.92–0.99, p 0.013). No statistically significant variations in trends were observed for CDI, MRSA BSI, and Candida BSI. Conclusions: The mixed AMS project was effective in reducing the use of major antibacterials and the incidence of CRKP BSI. Further research is needed to assess the extent of long-term benefits of semi-restrictive approaches.