Implementation of conditional reflex urine culturing decreases unnecessary antimicrobial use

Objective: To evaluate the impact of implementation of a conditional reflex urine culturing strategy on urine culture rates, antimicrobial use, and clinical outcomes in hospitalized adults. Design: Pre-post quasi-experimental study. Setting: Emergency departments and inpatient units within a large, integrated healthcare system in Northeast Ohio, comprising 10 medical centers. Patients: Adult patients with a urine culture ordered from June 1, 2018, to May 31, 2023. Methods: A system-wide intervention was implemented on June 1, 2020, requiring urinalysis (UA) with pyuria findings to trigger a urine culture order. We compared urine culture rates, antimicrobial use (measured by days of therapy [DOT] and days of antimicrobial spectrum coverage [DASC]), and clinical outcomes between pre-and post-intervention periods. Results: The intervention resulted in an 85.4% reduction in urine culture rates (0.54 vs 3.71 per 100 patient days). Antimicrobial use decreased, with DOT per 100 patient days dropping by 11.5% and DASC/DOT by 16.1%. No significant differences were observed in Clostridioides difficile infection rate, subsequent bloodstream infections with urinary pathogens, or mortality between pre- and post-intervention groups. Conclusions: A conditional reflex urine culturing strategy implemented as part of a diagnostic stewardship framework reduced urine culture and antimicrobial use without adverse clinical outcomes. This highlights the potential of diagnostic stewardship to optimize antimicrobial use in hospitalized adults.