1699 - Variation of Antimicrobial Resistance by Age Groups for Outpatient UTI Isolates in US Females: A Multicenter Evaluation From 2011 to 2019

Background: An estimated 12% of women experience ≥ 1 episode of urinary tract infection (UTI) annually. Incidence is bimodal, with peaks occurring in young, sexually active women (18–24 years) and in post-menopausal women. Previous studies suggest the prevalence of antimicrobial resistance (AMR) in UTI is rising; however recent AMR data for community-acquired UTI are lacking. We estimated the prevalence of AMR among US females with outpatient UTI in 2011–2019, stratified by age.

Methods: A retrospective, multicenter, cohort study of AMR among non-duplicate urine isolates in US females (≥ 12 years of age) from 296 institutions from 2011–2019 (BD Insights Research Database, Franklin Lakes, NJ). Phenotypes examined for Enterobacterales (ENT) were: extended spectrum β-lactamase positive (ESBL+; determined by commercial panels or intermediate/resistant to ceftriaxone, cefotaxime, ceftazidime or cefepime); nitrofurantoin (NFT) not-susceptible (NS); fluoroquinolone (FQ) NS; trimethoprim-sulfamethoxazole (TMP-SMX) NS; and NS to ≥ 2 or ≥ 3 drug classes (including ESBL+). Gram-positive phenotypes were, methicillin resistant S. aureus and S. saprophyticus and vancomycin-resistant Enterococcus. Isolates were stratified by patient age (≥ 12 to < 18, ≥ 18 to < 55, ≥ 55 to < 65, ≥ 65 to < 75, ≥ 75 years). Chi-square tests were used to evaluate AMR difference between groups.

Results: In total, urine isolates were collected from 106 to 296 (2011–2019) US sites. Overall, the prevalence of antimicrobial NS increased with age for all E. coli phenotypes (all P< 0.001; Table 1), and for non-E. coli ENT (all P< 0.001), except NFT NS, which decreased from 70.6% to 59.7% (P=0.002; Table 2). The greatest difference between age groups in prevalence of resistance was observed for FQ NS E.coli: 5.8% (≥ 12 to < 18 years) vs 34.5% (≥ 75 years). For the multi-drug resistant E. coli phenotypes, resistance increased with age, ranging from 4.8–22.4% and 0.9–6.5% for ≥ 2 and ≥ 3 drug NS, respectively. Overall, the prevalence of resistance for Gram-positive phenotypes increased with age (all P< 0.001; Table 3).Table 1. Prevalence of antimicrobial resistance among E. coli isolates in US females with outpatient UTI by age group.
Table 2. Prevalence of antimicrobial resistance among non-E. coli ENT isolates in US females with outpatient UTI by age group.
Table 3. Prevalence of antimicrobial resistance among Gram-positive isolates in US females with outpatient UTI by age group.


Conclusion: The prevalence of AMR in E. coli and non-E. coli ENT increased with age among US females presenting for care in the outpatient setting overall. A similar trend increase by age is also seen in Gram-positive isolates.