Background and importance Recent studies have reported an increase of antimicrobial use during the COVID-19 pandemic. The impact of overuse on the propagation of antimicrobial resistance could be an indirect adverse consequence of the pandemic.

Aim and objectives To describe the impact of the COVID-19 pandemic on antimicrobial prescription trends and analyse the relationship with the evolution of antimicrobial susceptibility.

Material and methods Descriptive study to investigate the prescription of antimicrobials (ATC group J01) and the evolution of resistance before and after the COVID-19 pandemic in adult patients admitted to a tertiary-care hospital.

Antimicrobial use was expressed into defined daily doses per 100 discharges (DDD/100D). We compared first-wave COVID (March-June 2020) versus pre-COVID (March-June 2019).

Antimicrobial sensitivity (EUCAST v11.0) was evaluated as a percentage of resistant bacterial strains isolated between January and June 2021 versus the pre-COVID situation (January-December 2019).

Results During the first wave, 4465 adult patients were admitted to the hospital versus 5318 in the same period of 2019). In this context antimicrobial consumption increased +79.09% (735.85/410.89 DDD/100D).

The most important changes in antimicrobials consumption compared to the pre-COVID period are detailed in table 1.

The most important changes in bacterial sensitivity are detailed in table 2.

Conclusion and relevance Important increase in hospital antimicrobial consumption was observed, especially for the beta-lactams and carbapenems.

Minimal changes in antimicrobial susceptibility was observed, detected only in Klebsiella spp, Pseudomonas aeruginosa and Enterococcus faecium.

Antimicrobial stewardship strategies can help to keep the consumption of antimicrobials within acceptable levels.

Conflict of interest No conflict of interest