Impact of Implementing an Outpatient Antimicrobial Stewardship Program on Urinary Tract Infection Management in a Private Hospital in Costa Rica.

BACKGROUND: Antimicrobial stewardship programs (AMS) improve antibiotic use in both hospital and outpatient (OP) settings. While AMS initiatives in Latin America have focused mainly on inpatient care, OP-specific interventions remain limited. Hospital Clínica Bíblica (HCB) had an AMS program for hospital settings but lacked structured OP activities. OBJECTIVES: To evaluate the implementation of an AMS-OP in a private hospital in Costa Rica, its impact on antibiotic prescribing patterns for urinary tract infections (UTIs), and its feasibility for broader application in the Latin American context. METHODS: A retrospective observational study with a pre- and post-intervention design was conducted. The analysis compared OP antibiotic prescribing for UTIs during the pre-AMS-OP period (July 2021-March 2022) and the post-AMS-OP period (July-December 2022). The AMS-OP was implemented from April to June 2022. Baseline compliance with CDC AMS-OP elements was assessed. A total of 269 OP UTI cases were analyzed, focusing on optimal antibiotic selection, physician adherence to clinical guidelines, and clinical outcomes, including recurrence and relapse. RESULTS: UTIs accounted for 163 (40.1%) of 407 OP antibiotic prescriptions. Pre-AMS-OP, 255 (62.7%) of the antibiotics prescribed belonged to the WHO Watch category. Post-AMS-OP, CDC compliance increased from 28.6% to 85.7%. Optimal antibiotic selection improved from 143 (53.8%) to 126 (95.2%) cases (p < 0.001). The optimal use of ciprofloxacin and levofloxacin improved by 31.3% (p = 0.028) and 60.0% (p = 0.027), respectively. Nitrofurantoin and fosfomycin use increased, while trimethoprim-sulfamethoxazole (TMP-SMX) and fluoroquinolones decreased. Physician adherence scores rose from 46.2 to 90.0. UTI recurrence decreased to 15 cases (11.9%, p = 0.005), and relapse rates fell to 3.1% (p = 0.07). CONCLUSIONS: Implementing AMS-OP based on CDC elements significantly improved antibiotic selection, physician guideline adherence, and clinical outcomes for UTIs in the OP setting. This strategy appears feasible and beneficial for OP care in Latin America.