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

The overuse of antimicrobials favors the dissemination of antimicrobial resistance, 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. 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. 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. 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.