Pathogen occurrence and antimicrobial resistance in long-term care units before and after the COVID-19 pandemic: an analysis from a Polish district hospital (2017-2023)

OBJECTIVES: The study aimed to analyse trends in pathogen occurrence and antimicrobial resistance patterns in two long-term care (LTC) units operating within a Polish district hospital from 2017 to 2023, with a particular focus on changes across the COVID-19 pandemic. METHODS: A retrospective observational study was conducted using epidemiological and microbiological data from two LTC units (nursing home and inpatient hospice) in Poland. Isolation rates (per 1,000 patient-days) for ESKAPE pathogens and Clostridioides difficile were analysed. The pre-pandemic period (2017-2019) was compared with the pandemic/post-pandemic period (2020-2023) using rate ratios (RR). Trends in the proportion of resistant isolates among the dominant Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii) were evaluated based on phenotypic surveillance criteria. RESULTS: The inpatient hospice and nursing home exhibited different epidemiological profiles. In the hospice, ESKAPE pathogen isolation rates decreased significantly after 2020 (RR = 0.55, 95% CI: 0.37-0.81), whereas the detection rate of C. difficile quadrupled (RR = 4.39, 95% CI: 1.51-12.75). Isolation rates remained low and stable in the nursing home. Across both units, the proportion of antimicrobial-resistant isolates increased sharply during the pandemic period. Notably, in selected pandemic and post-pandemic years, all analysed E. coli and K. pneumoniae isolates exhibited the ESBL phenotype, while all analysed A. baumannii isolates were carbapenem-resistant. CONCLUSIONS: The COVID-19 pandemic was associated with substantial changes in pathogen occurrence patterns in long-term care units and with increased antimicrobial resistance among key Gram-negative pathogens. The emergence of resistant phenotypes among clinically important Gram-negative pathogens, including ESBL-producing Enterobacterales and carbapenem-resistant A. baumannii isolates, poses a significant public health concern. These findings highlight the need for strengthened microbiological surveillance, antimicrobial stewardship, and infection prevention and control measures tailored to the specific care profiles of hospices and nursing homes.