Impact of the COVID-19 pandemic on vancomycin-resistant Enterococcus bloodstream infections: a 6-year study in Western Greece.

Background: Antimicrobial resistance is a critical and growing global health concern. While drug-resistant Gram-negative bacilli pose a significant threat, multidrug-resistant Gram-positive bacteria-such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), and β-lactamase-resistant Streptococcus pneumoniae-also present serious clinical challenges. Aim: This study provides an epidemiological analysis of resistant Gram-positive bacteria, focusing on VRE, at a tertiary university hospital in Western Greece from 2018 to 2023. Results: A total of 276 blood cultures with vancomycin-resistant Enterococcus spp. were recorded. A significant increase in VRE prevalence was observed in intensive care units (ICUs), with cases rising from 4 in 2020 to 36 in 2021. A broader increase across medical and surgical wards was noted in 2022-2023. Linezolid resistance remained low throughout the study period. Mortality data revealed a marked increase in deaths after 2020 compared to 2018-2019, coinciding with the rise in VRE-related bloodstream infections. The Coronavirus Disease 2019 (COVID-19) pandemic was associated with higher VRE rates in ICU patients, likely due to prolonged hospitalizations, increased use of invasive devices, and broad-spectrum antibiotic use. Resistance rates to both linezolid and tigecycline remained low, while daptomycin resistance showed an increasing trend the same period. Conclusion: The number of VRE increased over the study period. Linezolid and tigecycline remained largely effective, but emerging resistance patterns-particularly to daptomycin-underscore the urgent need for strengthened antimicrobial stewardship and the development of novel therapeutic options to address rising resistance among Gram-positive pathogens.