Impact of Rapid Molecular Diagnostic Testing on Outcomes of Patients With Vancomycin-Resistant Enterococcal Bacteremia.

Background: Vancomycin-resistant enterococci (VRE) bacteremia is associated with substantial mortality. Rapid molecular diagnostic testing (RMDT) that detects enterococci and vancomycin resistance genes from positive blood culture broths may lead to earlier appropriate antimicrobial therapy for VRE bacteremia, which could improve clinical outcomes. Methods: We conducted a retrospective cohort study of patients with VRE bacteremia from 2010 to 2019. RMDT that detects enterococci and vancomycin resistance genes from positive blood cultures was implemented in October 2014. We compared time to active antimicrobial administration, mortality, and other outcomes in patients whose positive blood cultures underwent RMDT (postintervention) and those whose did not (preintervention). Results: Of 577 eligible patients with VRE bacteremia, 237 (41.1%) had blood cultures that underwent RMDT. The RMDT cohort had shorter median time from culture collection until receipt of active antimicrobial therapy (21 vs 32 hours, P < .001) than the non-RMDT cohort. There was no difference in 30-day mortality (31.6% vs 36.5%, P = .230). A post hoc subgroup analysis excluding patients with leukemia (who received empiric VRE-active therapy based on Gram stain results) found that RMDT was associated with decreased 30-day mortality: 29.6% versus 40.8%, P = .037. On multivariate analysis, that improvement in 30-day mortality in patients without leukemia did not persist. Conclusions: RMDT was associated with decreased time to receipt of active antimicrobial therapy in VRE bacteremia. There was no improvement in mortality associated with the use of RMDT. RMDT for VRE bacteremia may improve time to identification and treatment of VRE bacteremia but does not clearly improve clinical outcomes.