SAVE ‘Stewardship antibiotica Verona’: Result of an enabling and multidimensional Antimicrobial Stewardship intervention promoting prescribing appropriateness across the entire surgical path of care

Background: As a part of the hospital-wide Antimicrobial Stewardship (AS) SAVE project, a Quality Improvement (QI) intervention was implemented in the surgical area of the Verona University Hospital. Rather than focusing on specific elements (i.e. Surgical Antibiotic Prophylaxis, SAP), the intervention was aimed at globally improving the antimicrobial prescribing practice across the entire surgical pathway. An enabling approach was adopted to foster surgeons to play a leading role in the optimizations of antimicrobial use in their wards. Methods: The QI intervention encompass a prolonged on the field training with an Infectious Disease (ID) specialist attending the clinical rounds daily for 4-8 weeks, followed by a 9-months auditing and feedback; an educational workshop, CME-accredited, was held between the two. The first phase was also capitalized for the development of ward-dedicated guidelines. The primary outcome was the variation in antibiotic consumption measured by Days of Therapy (DOTs) and Daily Defined Doses (DDDs) per 1000 patient-days (PDs). Variation in consumption, stratified according to the WHO AWaRe and the main classes of interest considering the epidemiological context (fluoroquinolones, carbapenems, and anti-MRSA agents), in-hospital mortality, length of hospital stay (LOS), incidence of Clostridium difficile infections (CDI), and carbapenem-resistant Enterobacteriaceae bloodstream infections (CRE-BSI) were the secondary outcomes. The interrupted-time-series analysis (ITSA) was used to evaluate the AS intervention effectiveness, comparing the 12-month pre- and post-intervention periods. Results: Eighty-six surgeons and 18 anesthesiologists were involved in 5 surgical and one surgical-dedicated Intensive Care Unit (ICU). Overall, 710 prescriptions were reviewed and the mean prevalence of patients receiving antibiotics ranged from 22% in the cardiac surgery to 74% in the ICU. Post-intervention global prescribing appropriateness exceeded 70% in all the wards, SAP appropriateness levels ranging 61-73 and not exceeding the 24-hours duration in more than 60%. The ITSA identified significant reduction in overall antimicrobial consumption in 3/5 wards, with downward slope in urology (-65 DOTs*1000PDs/month, P=0.038) and abruptly level change in traumatology and cardiac surgery (-111.6 DOTs*1000PDs P=0.032, -167 DOTs*1000PDs P=0.027). Although raw data showed lower WATCH usage in all the wards (from -27% to -43%), the ITSA confirmed significant desirable effects of the intervention only in the Cardiothoracic area (post-intervention: Cardiac surgery -10.9 DOT*1000PDs/month, P<0.001; ICU -83 DDDs*1000PDs/month, P< 0.001) where a significant reduction in the level of RESERVE (-142 DOTs*1000PDs, P<0.01; -251 DDDs*1000PDs, P=0.007), carbapenems, and anti-MRSA agents was also observed. Fluoroquinolones raw consumption decreased more than 60% everywhere; however, when assessed by ITSA, significant downward trends emerged only in Urology and General surgery (starting from higher baseline levels) as opposed to Traumatology and General Surgery, showing positive change in slope, presenting a sharp decrease in the pre-intervention year then stabilizing. The absence of significant variation in the in-hospital mortality and LOS confirmed the safety of the intervention. The incidence of C.difficile and CRE-BSI was low, with no significant trends emerging. Conclusion A QI intervention targeting the entire surgical pathways can enhance prescribing appropriateness and safely achieve valuable variation in antibiotic consumption. As great variability exists across different surgical specialities, a tailored approach in the intervention implementation and pre-definition of the desirable variation of targeted antimicrobial class consumption represent key elements for success. The study also provides useful insights prompting a reorganization of the ID consultation service to adequately address the peculiarity of the surgical area.