Risk Factors Associated With Antimicrobial Resistance and Adverse Short-Term Health Outcomes Among Adult and Adolescent Female Outpatients With Uncomplicated Urinary Tract Infection

Abstract

Background: Increasing antimicrobial resistance makes treating uncomplicated urinary tract infections (uUTIs) difficult. We compared whether adverse short-term outcomes among US female patients were more common when initial antimicrobial therapy did not cover the causative uropathogen. Methods: This retrospective cohort study used data from female outpatients aged ≥12 years, with a positive urine culture and dispensing of an oral antibiotic ±1 day from index culture. Isolate susceptibility to the antimicrobial initially dispensed, patient age, and history of antimicrobial exposure, resistance, and all-cause hospitalization within 12 months of index culture were evaluated for associations with adverse outcomes during 28-day follow up. Outcomes assessed were new antimicrobial dispensing, all-cause hospitalization, and all-cause outpatient emergency department/clinic visits. Results: Of 2366 uUTIs, 1908 (80.6%) were caused by isolates susceptible and 458 (19.4%) by isolates not susceptible (intermediate/resistant) to initial antimicrobial treatment. Within 28 days, patients with episodes caused by not susceptible isolates were 60% more likely to receive a new antimicrobial versus episodes with susceptible isolates (29.0% vs 18.1%; 95% confidence interval, 1.3-2.1; P