P-70. A Comparison of Clinical and Safety Outcomes for Patients with Vancomycin Resistant Enterococcus Faecium Bacteremia Treated with High Dose Daptomycin Based on Isolate MIC

Abstract Background Daptomycin (DAP) is a frequently utilized treatment option for patients with vancomycin-resistant Enterococci (VRE) bacteremia. Prior study data has shown poorer clinical outcomes for patients with VRE bacteremia and isolate MICs of >1µg/mL who were treated with standard dosing DAP (6mg/kg/day). The purpose of this project is to compare clinical and safety outcomes among patients with VRE faecium bacteremia and an isolate MIC of 2-4 µg/mL based on daptomycin dose. Methods This is a retrospective chart review assessing outcomes for patients ≥18yo treated with DAP for VRE bacteremia. Patients were excluded if they had concurrent treatment with a VRE active agent, were pregnant, had a primary infectious focus of pneumonia. Primary outcome is 14-day mortality based on DAP dose used (< 10mg/kg vs ≥10mg/kg) for isolates with an MIC of 2 µg/mL or 4µg/mL. Secondary outcomes include analysis of 14-day mortality based on both DAP dose used and isolate MIC, hospital mortality, time to microbiological clearance, microbiological failure, and clinical failure. Results 95 pts with VRE bacteremia were included. There were 53 pts in the high DAP group (< 10mg/kg) and 42 pts in the low DAP dose group (≥10mg/kg). Baseline and treatment characteristics were similar between groups. 14-day mortality was low overall and not significantly different between groups (7% vs. 6%, p=0.72). There were also no differences between in-hospital mortality, microbiological failure, and clinical failure. There were no differences in adverse events. Median time to microbiological clearance was faster in the high-dose DAP group (2 [2-4] vs. 3 [2.5-5] days, p=0.02). There were no differences in outcomes between groups depending on MIC; however time to microbiological clearance was significantly lower in the high-dose DAP group when MIC was 4 µg/mL (2 [2-5] v. 3 [2-6], p=0.04) Conclusion Low-dose compared to high-dose DAP was not associated with 14-day mortality. Low-dose DAP was not significantly associated with overall hospital mortality, microbiological failure, or clinical failure. High-dose DAP was associated with decreased time to microbiological clearance. High-dose DAP dosing does not appear to be associated with an increased risk of adverse drug events compared to low-dose. Disclosures All Authors: No reported disclosures