P-870. Daptomycin-Susceptible vs. Daptomycin-Non-susceptible <i>Enterococcus</i> Bloodstream Infections: Rates and Predictors of Treatment Failure and Predictors of Daptomycin Resistance

Abstract Background Daptomycin is a well-tolerated option to treat resistant enterococci; however, updated breakpoints from the Clinical Laboratory and Standards Institute (CLSI) have led to increasing numbers of ‘susceptible, dose-dependent’ (SDD) or daptomycin non-susceptible (DNS) isolates. Methods This study was to determine if isolation of daptomycin-sensitive enterococcal (DSE) or daptomycin-non-susceptible enterococcal (DNSE) isolates from the blood impacts patient outcomes. A retrospective, observational, cohort of patients within the Veteran’s Affairs (VA) Healthcare System from 1 January 2017 to 31 December 2021 with at least 1 blood culture positive for Enterococcus faecalis or E. faecium was identified. Patients were analyzed in 3 cohorts: 1) all included patients, 2) only patients with minimum inhibitory concentration (MIC) data available, and 3) E. faecium isolates and DSE isolates only. The primary outcome of treatment failure was a composite of 30-day mortality and microbiological failure. Two multivariate regressions were conducted - one to establish predictors of treatment failure and one to establish predictors for daptomycin non-susceptibility. Results Two hundred four patients were included (90 DSE, 114 DNSE). In cohort 1, 63.3% (57) DSE patients experienced failure vs. 58.8% (67) in the DNSE group (p = 0.56). Sixty-nine percent (40/58) of DSE patients failed in cohort 2 vs. 56.4% (35/62) of DNSE patients (p = 0.157), and 69% (40/58) of DSE and 64.4% (56/87) of DNSE failed in cohort 3 (p = 0.56). Multivariate regression revealed infectious diseases (ID) consultation (OR 0.402; 95% CI, 0.176-0.918; p = 0.030) was associated with reduced risk of failure, while infection with vancomycin-resistant enterococcus (OR 2.04; 95% CI 1.028-4.049; p = 0.04) and endocarditis/endovascular source of infection (OR 4.33; 95% CI 1.34 – 13.99; p = 0.01) were associated with increased risk of failure. Previous beta-lactam and vancomycin exposure were associated with increased risk of DNSE. Conclusion No significant difference in failure between patients with DSE and DNSE bacteremias was observed; however, ID consultation was found to be protective, and previous antibiotic exposure was associated with increased DNSE risk. Disclosures All Authors: No reported disclosures