A 5-Year Epidemiological Study of Monomicrobial Enterococcal Bloodstream Infection in a Population-Based Cohort.

Background: The incidence, epidemiology, and clinical characteristics of enterococcal bloodstream infection (BSI) have not previously been studied on a population-based level in the United States.

Methods: We utilized the Expanded Rochester Epidemiology Project medical records linkage system to conduct a contemporary 5-year, retrospective, population-based study of monomicrobial enterococcal (ME) BSI among adult residents of 8 counties in southeast Minnesota from January 1, 2018 to December 31, 2022.

Results: A total of 109 cases of ME-BSI were identified. The overall age- and sex-adjusted incidence rate was 6.7 per 100 000 person-years (95% confidence interval, 5.4-7.9). Multivariable analysis revealed that male sex (P < .001) and older age (P < .001) were each independently associated with increased incidence, whereas no temporal association was demonstrated (year effect, P = .475). The median age of incident cases was 76.8 years (interquartile range, 65.0-83.3). Urinary tract source was the most common presumed source (42.2%), and Enterococcus faecalis was the predominant (83.5%) pathogen. Overall, 14.4% of patients met modified Duke criteria for definite infective endocarditis. Cumulative mortality was 28.4% at 12 weeks and 43.1% at 1 year.

Conclusions: In this population-based study, ME-BSI was significantly associated with older age and male sex. There was a high rate of mortality at 12 weeks and 1 year, with ∼1 out of 7 cases complicated by definite infective endocarditis. These findings underscore the importance of ongoing investigation of this syndrome.