A 5-Year Population-Based Study of Polymicrobial Enterococcal Bloodstream Infection in Southeast Minnesota

To study the incidence, epidemiology and clinical outcome of polymicrobial enterococcal bloodstream (PE-BSI) infection in a geographically defined population of adults in the United States.

All adult (age ≥18 years) residents within 8 counties in southeast Minnesota who developed a first-ever episode of PE-BSI from January 1, 2018, through December 31, 2022, were identified using the Expanded Rochester Epidemiology Project (E-REP) medical records linkage system. Incidence rates were based on the number of cases divided by the person-years in the population.

During the 5-year study period, 66 incident PE-BSI cases were observed (median age 71.3 years; 72.7% male), corresponding to an age- and sex-adjusted incidence rate of 4.1 cases per 100,000 person-years. Multivariable analysis showed that older age and male sex were associated with increased PE-BSI incidence (both P<.001). The most common source of bloodstream infection was non-urinary intra-abdominal (40.9%). Enterococcus faecalis was the most common bloodstream isolate (69.7%). Primary concomitant bloodstream organisms were Escherichia coli (18.2%), Staphylococcus aureus (15.2%), and coagulase-negative Staphylococcus (15.2%). Despite low rates of definite infective endocarditis (3.2%) and BSI relapse (3.0%), mortality rates following PE-BSI were relatively high (31.8% at 12 weeks, 47.3% at 1 year).

In this population-based study of 66 incident PE-BSI cases, increased incidence was associated with older age and male sex. A non-urinary intra-abdominal source was most often detected and cumulative mortality rates were high.