Temporal Trends and Mortality of Vancomycin-Resistant Enterococcus Bacteremia—A Six-Year Retrospective Cohort Study in a Tertiary Hospital in Greece

Background: Vancomycin-resistant Enterococcus (VRE) bacteremia represents a major therapeutic and epidemiological challenge, particularly in regions with high antimicrobial resistance rates such as Southern Europe. Longitudinal local data are essential to guide infection control and antimicrobial stewardship strategies. This study aimed to evaluate temporal trends in incidence, management, and mortality of VRE bacteremia in a tertiary care center in Greece over a six-year period, including comparison before and after the coronavirus disease 2019 (COVID-19) pandemic. Methods: This retrospective observational study included adult patients with VRE bacteremia at the University Hospital of Heraklion, Greece, from 2018 to 2023. Demographic and clinical data, such as the Pitt Bacteremia Index (PBI), as well as microbiological, and treatment data were collected from patient records. Incidence was calculated per 10,000 patient-days. Comparisons were performed between survivors and non-survivors and between pre- and post-COVID-19 eras. Multivariate regression analysis was used to identify predictors of in-hospital mortality. Results: A total of 96 patients were included (mean age 68.6 ± 14.5 years; 56.3% male). The incidence of VRE bacteremia increased more than five-fold during the study period, from 0.242 cases per 10,000 patient-days in 2018 to a peak of 1.344 per 10,000 patient-days in 2022, remaining elevated in 2023 (1.001 per 10,000 patient-days). The overall in-hospital mortality was 54.2%. Non-survivors had significantly higher PBI scores compared to survivors (median 2.5 vs. 0, p = 0.005). In the multivariate analysis, higher PBI was independently associated with in-hospital mortality [odds ratio: 1.449 (95% confidence intervals: 1.166–1.801)]. Appropriate empirical therapy was administered in 41.7% of cases and was not significantly associated with survival. Post-COVID-19 patients were older (69.9 vs. 61.4 years, p = 0.0365), and antimicrobial regimens were more frequently adjusted according to susceptibility testing (55.7% vs. 18.2%, p = 0.0141), but mortality did not significantly differ between periods. Conclusion: VRE bacteremia incidence increased dramatically over the six-year study period in our tertiary center, with persistently high mortality exceeding 50%. Severity of illness at the diagnosis of bacteremia, as measured by the PBI, was an independent predictor of in-hospital mortality. Strengthened infection prevention measures, optimized antimicrobial stewardship, and early aggressive management are urgently needed to mitigate the growing burden of VRE bacteremia.