Impact of COVID-19 pandemic on antimicrobial resistance of Proteus mirabilis in a Brazilian hospital.

This study analyzes the resistance and virulence profiles of Proteus mirabilis isolates obtained from patients admitted to the University Hospital of Londrina, Paraná, between 2019 and 2022. We evaluated the antimicrobial resistance phenotypes, genes associated with resistance, biofilm formation through a phenotypic assay, and the presence of specific virulence genes. When comparing the "pre-pandemic" (2019) and "pandemic" (2020-2022) periods, we observed an increase in resistance rates to all tested antimicrobials. Multidrug-resistant (MDR) pathogens producing extended-spectrum β-lactamase (ESBL) phenotypes were isolated in both periods, but their occurrence was significantly higher during the pandemic. We also observed an increase in the frequency of nearly all studied resistance genes. The virulence profiles remained largely unchanged. Analysis of patients' clinical and demographic data revealed that those hospitalized during the pandemic were older, required longer hospital stays, and had a higher usage of invasive devices. These findings suggest that the recent COVID-19 pandemic has impacted the antimicrobial resistance of P. mirabilis, a bacterium of significant clinical interest associated with urinary tract infections (UTIs) and healthcare-associated infections (HAIs).