Antibiotic Resistance of Urinary Tract Infection Recurrences in a Large Integrated US Healthcare System

Abstract

Abstract Background Data on antibiotic resistance of uropathogens for urinary tract infection (UTI) recurrences are lacking. Methods In a retrospective cohort of adults at Kaiser Permanente Southern California with culture-confirmed index uncomplicated UTI (uUTI) between January 2016 and December 2020, we examined the number and characteristics of subsequent culture-confirmed UTIs through 2021. Results We identified 148 994 individuals with a culture-confirmed index uUTI (88% female, 44% Hispanic; mean age, 51 years [standard deviation, 19 years]), of whom 19% developed a subsequent culture-confirmed UTI after a median 300 days (interquartile range, 126–627 days). The proportion of UTI due to Escherichia coli was highest for index uUTI (79%) and decreased to 73% for sixth UTI (UTI 6) (P for trend < .001), while the proportion due to Klebsiella spp increased from index UTI (7%) to UTI 6 (11%) (P for trend < .001). Nonsusceptibility to ≥1 and ≥3 antibiotic classes was observed in 57% and 13% of index uUTIs, respectively, and was higher for subsequent UTIs (65% and 20%, respectively, for UTI 6). Most commonly observed antibiotic nonsusceptibility patterns included penicillins alone (12%), and penicillins and trimethoprim-sulfamethoxazole plus ≥1 additional antibiotic class (9%). Conclusions Antibiotic nonsusceptibility is common in UTIs and increases with subsequent UTIs. Continuous monitoring of UTI recurrences and susceptibility patterns is needed to guide treatment decisions.