The impact of a non-restrictive Antimicrobial Stewardship Program in the emergency department of a secondary-level Italian hospital

Evidence supporting the effectiveness of Antimicrobial Stewardship (AMS) Programs in the emergency department (ED) setting is limited. We conducted a prospective cohort study to assess the efficacy of an AMS program in an ED and a short-stay observation unit. The intervention included periodic prospective audits (twice a week), conducted by four infectious disease consultants. Primary outcomes included the difference in the hospital mortality rate, antibiotic consumption, and the incidence of bloodstream infections (BSI) caused by multidrug resistant (MDR) bacteria, before March 2020-February 2021 and after March 2021-February 2022 when the program was implemented. Interrupted time-series analysis was performed to assess the effect of our program. During the 12-month program, we performed 152 audits and evaluated 366 antibiotic therapies out of a total of 853 patients admitted. In the intervention period, we observed a non-statistically significant decrease in total antibiotic consumption, with a change in level of - 31.2 defined daily dose/100 patient-days (PD) (p = 0.71). Likewise, we found no significant variations in the rate of BSI due to MDR Gram-positive (CT - 0.02 events/PD, p = 0.84), MDR Gram-negative bacteria (CT 0.08, p = 0.71), or Candida spp. (CT 0.008, p = 0.86). Conversely, we found a significant decrease in the mortality rate between the pre- and post-intervention periods (- 1.98 deaths/100 PD, CI - 3.9 to - 0.007, p = 0.049). The Antibiotic Stewardship Program in the ED was associated with a significant decrease in the mortality rate. More high-quality studies are needed to determine the most effective ASP strategies in this unique setting.