Predictors of mortality of Enterococcus faecium bloodstream infections: results from a 5-year retrospective study at Padua University Hospital

Objectives Enterococcus faecium (EF) bloodstream infections (BSIs) cause significant morbidity and mortality in health care settings. We herein report a cohort of EF BSIs with the aim of identifying predictors of 30-day in-hospital mortality. Methods This was a retrospective cohort study including hospitalized patients with EF BSIs from 2019 to 2023. We collected data on demographic characteristics, clinical and microbiological variables, laboratory findings, treatments, and deaths. Cox proportional hazards models were used to estimate hazard ratios with 95% confidence intervals for 30-day in-hospital mortality, to quantify the prognostic significance of risk factors after multivariable adjustment. A backward variable selection process was implemented in the Cox regression model to identify risk factors significantly associated with mortality. Results A total of 604 patients were included. The overall 30-day in-hospital mortality rate was 25.8%. Significant predictors of mortality included the presence of septic shock, Pitt bacteremia score values ≥2, and liver cirrhosis, while early source control and infectious diseases consultation were associated with a reduction in mortality rates. No statistically significant differences were observed in mortality between vancomycin-susceptible and vancomycin-resistant BSIs. Conclusions Mortality in EF BSIs was influenced by host- and disease-specific factors, including disease severity. Vancomycin resistance did not appear to have an impact on mortality. Early source control and infectious disease consultation played a critical role in improving survival. Future research should focus on prospective validation of these predictors and the development of tools and scores for early identification of high-risk populations, optimizing clinical management and patient outcomes.