Urinary Enterobacterales resistance increased after March 2020 in retrospective single-center analysis

A retrospective analysis of adult urine cultures found increased antimicrobial resistance among Enterobacterales after March 11, 2020, particularly to beta-lactams and fluoroquinolones. The study included 13,551 isolates from adult inpatients and outpatients at a single tertiary care center between January 1, 2016, and September 30, 2024. Escherichia coli accounted for 84.9% of the isolates and Klebsiella species for 11.0%.

The researchers divided results into two periods: before March 11, 2020, designated the pre-COVID-19 period, and the subsequent period, designated the post-COVID-19 period. Only urine cultures that yielded Enterobacterales were included. Antimicrobial susceptibility testing was performed with the VITEK 2 system, and resistance patterns were analyzed separately for inpatient and outpatient populations.

In the post period, resistance to beta-lactams and fluoroquinolones increased significantly, with p-values below 0.005 for most agents tested among E. coli isolates. Resistance to carbapenems and beta-lactam/beta-lactamase inhibitor combinations also increased, including among outpatient isolates. By contrast, resistance to aminoglycosides and trimethoprim-sulfamethoxazole remained stable or decreased in the post period. Nitrofurantoin retained relatively low resistance rates.

The abstract reports an association between the later study period and higher resistance to several antimicrobial classes among urinary Enterobacterales, but it does not establish that the COVID-19 pandemic caused the changes. The retrospective, single-center design restricts the findings to the analyzed population and urine cultures, while the absence of reported adjustments or other study-level details in the supplied abstract limits broader interpretation. The authors emphasized the value of continuous local surveillance, empirical-treatment optimization, antimicrobial stewardship, and infection-control practices in hospital and community settings.

Subject of Research: Retrospective analysis of antimicrobial resistance among urinary Enterobacterales before and after March 11, 2020

Article Title: Impact of the COVID-19 pandemic on the distribution and antimicrobial resistance patterns of urinary pathogens: a retrospective analysis from a single tertiary care center

Article References: Özbay Haliloğlu, E. N., & Tekin Taş, Z. (2026). Impact of the COVID-19 pandemic on the distribution and antimicrobial resistance patterns of urinary pathogens: a retrospective analysis from a single tertiary care center. BMC Infectious Diseases. https://doi.org/10.1186/s12879-026-14227-0

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DOI: 10.1186/s12879-026-14227-0

Keywords: COVID-19 period, urinary pathogens, Enterobacterales, antimicrobial resistance, Escherichia coli, Klebsiella, antibiotic susceptibility, retrospective study, tertiary care, Impact, COVID-19, pandemic