Trends in the epidemiology of extended-spectrum beta-lactamase-producing Enterobacterales - Boulder County, Colorado, 2020-2022.

Purpose: Extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E) are serious antibiotic resistance threats. We describe trends in epidemiological and clinical characteristics of ESBL-E cases in Boulder County, Colorado from 2020 to 2022.

Methods: The Colorado Department of Public Health and Environment (CDPHE) and Boulder County Public Health conduct population-based surveillance for ESBL-E as part of the Emerging Infections Program-Healthcare-Associated Infections Community Interface. Trained epidemiologists abstracted data from patient medical records from the year prior to incident specimen collection through 30 days after.

Results: There were 1036 ESBL-E cases. Annual case counts increased from 2020 to 2022 (256, 316, and 464, respectively). The rate of ESBL-E infections per 100,000 population increased (77.4 in 2020, 96.6 in 2021, and 141.7 in 2022). Most samples were collected from outpatient settings (n = 812, 92.2 %) and Escherichia coli was the most common organism identified (n = 789, 89.6 %). Most case-patients had a lower urinary tract infection (UTI) (n = 757, 85.9 %), which increased by year (p = 0.03).

Conclusions: ESBL-E counts and incidence rates in Boulder County increased from 2020 to 2022. Cases most commonly presented with E. coli urinary tract infections in the outpatient setting. Strategies to combat antibiotic resistance should target ESBL-E in community settings.