Targeting Overtreatment of Asymptomatic Bacteriuria in the Emergency Department: Results from a Quasi-Experimental Intervention Programme based on Education and Audit

Background: Asymptomatic bacteriuria (ASB) is frequently overtreated in emergency departments (ED), contributing to antimicrobial resistance without improving clinical outcomes. Rapid decision-making and high patient turnover in the ED increase the risk of unnecessary antibiotic use. Methods: A quasi-experimental study was conducted in the ED of a tertiary hospital in Barcelona, Spain, from January 2024 to June 2025. The intervention included targeted education for ED staff and daily audit-feedback on antibiotic prescriptions for suspected ASB. Outcomes were compared with a six-month pre-intervention period. The primary outcome was 30-day return visit to the ED for Urinary Tract Infection (UTI) with the same microbiological isolate. Secondary outcomes included 30-day all-cause mortality, overall UTI return visit to the ED, antimicrobial consumption (Daily Defined Dose/1,000 admissions), and urine culture requests. Results: A total of 130 patients in the pre-intervention period and 127 patients in the intervention period were included. In the intervention period, antibiotic discontinuation was recommended in 96 (75.6%) patients; acceptance rate was 29.2%. Despite limited acceptance, antimicrobial consumption declined, with cefalosporins reduced by 21% and carbapenems by 24%. Urine culture requests fell by 16.1%, and uropathogen isolates decreased by 15.9%. Clinical outcomes were similar between both periods: 30-day return visit to the EDs for UTI with the same isolate dropped from 6.2% to 1.6% (p-value=0,103), overall UTI return visit to the EDs from 8.5% to 4.7% (p-value=0.316), and 30-day mortality remained stable (6.2% vs. 3.9%, p-value=0.571), no statistically significant differences across all variables. Conclusions: This program reduced inappropriate antibiotic use and unnecessary urine testing in the ED without compromising patient safety. These results highlight educational and audit-feedback intervention as a safe, practical, and impactful antimicrobial stewardship strategy in high-pressure clinical settings as the ED.