Introduction: Inappropriate urine culture testing can lead to unnecessary antibiotics use and antimicrobial resistance. We evaluated the implementation of a stepwise stewardship intervention, with a focus on the appropriateness of urine culture orders and antibiotic use.Methods: We conducted a quasi-experimental study from August 2021 to Jun 2023 at a teaching hospital in Riyadh, Saudi Arabia. We included adult patients with urine culture orders. A stepwise antimicrobial stewardship intervention was implemented in two phases. In the first phase, a clinical decision support (CDS) tool was introduced in February 2022. In the second phase, a reflux urine culture was implemented in January 2023. Our outcomes were the percentage of inappropriate urine cultures ordered and antibiotic use. Outcomes were assessed at baseline, after the CDS intervention, and after the reflux urine culture intervention. We used multivariable logistic regression to estimate adjusted odds ratio, controlling for potential confounding variables. Results: During the pre-intervention period, the percentage of inappropriate urine culture order was 41.6%. Following the implementation of the first intervention—CDS—the percentage decreased to 36.4%. Subsequently, with the addition of reflux urine culture in the second phase of the stepwise intervention, the percentage further decreased to 28.6% (p value=<0.001). The stepwise intervention was associated with 15 lower odds of inappropriate urine culture ordering (adjOR 0.85; 95%CI 0. 0.69 – 0.90; p = 0.027). A significant reduction in Unnecessary antibiotics was observed across the three phases: 72.9% pre-intervention, 85.7% post-CDS, and 25% post-CDS and reflux urine culture (p <0.0001). The stepwise intervention was associated with 75% reduction in unnecessary antibiotic use (aOR 0.25; 95% CI 0.17 – 0.37, p <0.001)

Conclusions: This stepwise intervention suggest that each intervention contributed incrementally to decrease inappropriate urine culture and unnecessary antibiotic use.