[Impact of the COVID-19 pandemic on antimicrobial resistance].

OBJECTIVES: The COVID-19 pandemic has had a major impact on the healthcare system, which has been forced to manage large numbers of patients, including those with respiratory insufficiency and in need of oxygen therapy. Due to concerns about bacterial co-infection, antibiotic therapy was administered to many patients. The aim of the present study was to compare antimicrobial resistance in intensive care patients in the pre-pandemic and pandemic periods. MATERIAL AND METHODS: Patients hospitalized at the Department of Anesthesiology, Resuscitation and Intensive Care Medicine of the University Hospital Olomouc in the pre-COVID-19 period (2018-2019) and during the pandemic (2020-2021) were enrolled in the study. Clinical samples from the lower respiratory tract were routinely collected twice a week, with one strain of a given species first isolated from each patient being included in the study. RESULTS: While several bacterial species (Escherichia coli, Proteus mirabilis and Haemophilus influenzae) were found to occur less frequently, an increased occurrence was documented for Enterococcus faecium, Serratia marcescens and Klebsiella variicola. Overall, however, it can be concluded that there was no major change in the frequency of bacterial pathogens isolated from the lower respiratory tract during the COVID-19 period. Similarly, with only a few exceptions, antimicrobial resistance did not change significantly. More significant increases in resistance to piperacillin/tazobactam, cefotaxime, ciprofloxacin and gentamicin have been demonstrated for Serratia marcescens. However, a decrease in the resistance of Pseudomonas aeruginosa and Burkholderia cepacia complex to meropenem was also observed. CONCLUSIONS: There was no significant change in the frequency of bacterial pathogens and their resistance to antibiotics during the COVID-19 pandemic. However, there was an increase or decrease in the percentage of some species and in their resistance.