Associations between neighbourhood-level median household income and outpatients' risk of antibiotic non-susceptible uropathogens in a major urban centre, USA.

Introduction: Resistance to first-line antibiotics among urinary tract infections continues to rise, but how neighbourhood-level socioeconomic status impacts this risk remains unclear. We examined the effect of neighbourhood-level income on a patient's risk of having a uropathogen non-susceptible to trimethoprim/sulfamethoxazole (TMP/SMX) or nitrofurantoin.

Methods: We used electronic health record data and antibiotic susceptibility test results for urinary Escherichia coli and Klebsiella pneumoniae collected at Emory Healthcare outpatient facilities in greater Atlanta between October 2022 and September 2023. We determined patients' block group median household income (MHI) using their residential addresses and 2017-21 US census data. We performed a logistic regression with a priori risk factors using a generalized estimating equation, with subgroup analysis by organism and for patients with diabetes mellitus.

Results: We included 9325 urine E. coli and K. pneumoniae isolates from 3867 outpatients. Compared to uropathogenic E. coli, K. pneumoniae were more likely to be non-susceptible to nitrofurantoin (P < 0.001) and less likely to be non-susceptible to TMP/SMX (P < 0.001). Compared to the lowest MHI quintile, patients in the highest MHI quintile neighbourhoods had 0.78 odds of harbouring a non-susceptible uropathogen (95% CI: 0.64, 0.95) after controlling for patient age, sex and race/ethnicity, along with neighbourhood-level characteristics. This association was stronger for K. pneumoniae infections and non-significant among people with diabetes.

Conclusions: Higher neighbourhood-level MHI was associated with lower individual risk of harbouring a first-line antibiotic-non-susceptible uropathogen.