Abstract
Background
Enterococcus species commonly cause bloodstream infections (BSIs) with E. faecium infections considered especially worrisome due to association with vancomycin resistance via expression of the vanA gene. However, it is unclear if there is an association with E. faecium’s drug resistance potential and increased morbidity or mortality. Here we aimed to assess the severity of disease and mortality of patients with E. faecalis versus E. faecium BSIs, including subgroup analysis of vancomycin resistant E. faecium (VRE).
Methods
We conducted a retrospective, observational cohort study at a large urban academic center. Adult patients admitted from January 2018 to October 2022 with either E. faecalis or E. faecium BSI were included. Variables collected, determined a priori, included history of previous antibiotic use, malignancy, transplant status, and bacteremia source. Outcome variables of interest were ICU stay, length of stay, and mortality.
Results
There was a total of 182 total cases of E. faecalis and E. faecium BSI, 123 and 65, respectively, including 6 cases with both species (Table 1). Patients with E. faecium had higher median Pitt bacteremia scores (2 [IQR 0-4] versus 1 [IQR 0-3], p = 0.02) and longer median length of stay (30 [IQR 12-51] versus 15 [IQR 8-27], p < 0.001). There was statistically higher all-cause mortality at time of data collection in the E. faecium (60% vs 41%, p = 0.01) and VRE cohorts compared with E. faecalis (63% vs. 41%, p = 0.02). Kaplan-Meier curve (Figure 1) demonstrates decreased survival in the E. faecium cohort compared to E. faecalis within the first 100 days after bacteremia (HR 1.84, p = 0.01). Of note, a difference in 90-day all cause mortality was only statistically different in the entire E. faecium cohort when compared to the E. faecalis cohort. (45% vs 29%, p = 0.04), in contrast to the VRE cohort (43% vs 29%, p = 0.12).
E. faecalis vs E. faecium results
Comparison of select variables
E. faecalis vs vancomycin resistant E. faecium results
Comparison of select variables
Conclusion
E. faecium BSIs appear associated with longer, more clinically severe hospital courses and significantly increased mortality, specifically 90-day mortality when compared to E. faecalis BSIs. Future inquiries should assess the extent to which E. faecium serves as an index versus driver of poor clinical outcomes and strategies to mitigate the associated mortality.
Disclosures
James Sanders, PhD, PharmD, Merck & Co., Inc.: Grant/Research Support|Shionogi Inc.: Grant/Research Support