Clinical characteristics and predisposing risk factors for Enterococcus faecalis and Enterococcus faecium blood stream infections: a prospective multi-centre cohort study from the PROBAC projec

Abstract

Background Enterococci are currently ranked second in terms of causative pathogens for gram-positive bloodstream infection (BSI) and are associated with significant morbidity and mortality. The two most common species are Enterococcus faecium and E. faecalis, which show important differences in terms of resistance patterns. Only a few studies have explored the differential risk factors for the two species. The study aimed to compare the predisposing risk factors for E. faecalis and E. faecium BSI and to explore the differences between them. Methods The study is a post-hoc analysis of the PROBAC project, a national multicenter, observational, prospective cohort study conducted in 26 Spanish hospitals between October 2016 and March 2017. For this sub-analysis, patients with a polymicrobial and monomicrobial BSI due to E. faecalis or E. faecium were eligible. Multivariable logistic regression model was performed to explore the independent predictors for BSI onset caused by E. faecium vs. E. faecalis. Results In total, 431 patients were included, with 267 BSI caused by E. faecalis and 166 by E. faecium, 128 (28.8%) BSI were polymicrobial. Median age was 72 (IQR 62-82), 33.4% female. The general characteristics and differences between E. faecalis and E. faecium are shown in Table1. In the bivariate analysis, no differences in BSI clinical presentation or clinical outcomes were observed. The source of infection and types of infection acquisition are shown in Figure1. In the multivariable analysis (Table2), Charlson comorbidity index ≥3 [adjusted OR=1.96(95%CI=1.07-3.58), p=0.03], previous use (<30 days) of penicillins [aOR=1.99(1.19-3.32), p=0.009] or carbapenems [aOR=2.46(1.16-5.23), p=0.002], hospital-acquired BSI [aOR=2.66(1.65-4.37), p<0.001], and biliary-tract source [aOR=3.28(1.79-6.02), p<0.001] were independent factors associated with E. faecium BSI. Instead, congestive heart failure [aOR=0.48(0.25-0.91), p=0.025], previous cerebrovascular incident [aOR=0.43 (0.20-0.92) p=0.03], and urinary-tract source [aOR=0.48 (0.25-0.91), p=0.024] were independent factors associated with E. faecalis BSI.