Identifying Associated Risk Factors for Persistent Vancomycin Resistant Enterococcal Bacteremia

Enterococcal bloodstream infections (BSIs) that are caused by vancomycin-resistant enterococcus (VRE) have concerned experts due to the limited number of available treatment options, as well as the high rates of mortality.

Risk factors for persistence have been analyzed for Staphylococcus aureus bacteremia, however there have not been any conducted on patients with persistent VRE BSIs.

Investigators from Stanford Health Care, in collaboration with the UC San Diego Skaggs School of Pharmacy and Pharmaceutical Sciences and the Stanford University School of Medicine, have conducted a study that aimed to identify risk factors associated with persistent VRE BSIs.

The data was presented at the 23rd Annual Making a Difference in Infectious Disease Meeting 2021 virtual sessions.

The single-center, retrospective, case-control study included 108 participants who were admitted to the hospital between 2016-2020 with a VRE BSI. Patients admitted to the study had a persistent case of bacteremia, which was defined as positive blood cultures with VRE for four days or more despite receiving active antibiotic therapy.

Those who had a resolving case of bacteremia, with subsequent blood cultures documented to be negative within 4 days of initiation of active antibiotic therapy were the control arm of the study.

Investigators employed logistic regression to assess risk factors associated with persistent VRE bacteremia.

Results from the study demonstrated that in-hospital mortality and recurrent bacteremia occurred in 58% and 17% of patients in the persistent VRE BSI group, compared to 40% and 6% in the resolving VRE BSI group.

Risk factors for persistent bacteremia were identified as intermittent hemodialysis (p=0.034), pleural fluid as the primary site of infection (p=0.01), high-grade bacteremia (p=0.002), lack of source control (p<0.001), and >72 hours until source control (p=0.007) in the bivariate analysis.

“Persistent VRE BSI was associated with worse clinical outcomes, including a higher incidence of mortality and recurrent bacteremia. Intermittent hemodialysis and pleural fluid as the primary site of infection were identified as risk factors for persistent bacteremia,” the authors wrote. “Management strategies in the persistent bacteremia group were highly heterogenous, highlighting the need for additional research in this area.”