137. Impact of Rapid Susceptibility Testing on Outcomes in Patients with Bacteremia

BACKGROUND: Early organism identification via rapid diagnostics has been shown to reduce time to effective antimicrobial therapy and improve patient outcomes in patients with bacteremia, but antimicrobial susceptibility testing is still required to optimize therapy. The objective of this study was to determine the impact of an institution-specific rapid susceptibility testing method on outcomes in patients with bacteremia. METHODS: This was a retrospective pre- and post-intervention study of 100 adult patients with bacteremia. Patients were excluded if they had polymicrobial infection, fungemia, blood cultures collected at outside hospitals, or if they expired prior to susceptibility results. Patients were identified through a report containing positive blood cultures from October 2017 to February 2018 (pre-intervention [PrI]) and October 2018 to February 2019 (post-intervention [PoI]). The primary endpoint was the rate of clinical failure (a composite of 28-day mortality or bacteremia persisting greater than 6 days). Secondary endpoints included microbiologic outcomes, time to effective and optimal therapy, length of stay (LOS) and therapy adjustments. RESULTS: Baseline characteristics were similar between groups; a third of the patients were immunosuppressed (Table 1). The most common sources of infection were urinary and intra-abdominal, and the most common organisms identified were E.coli and Klebsiella spp. No significant difference in the rate of clinical failure was identified between PrI and PoI (24% vs. 18%, P = 0.6242) (Table 2). In the PoI, the time to identification, susceptibility results, and effective therapy was significantly shorter with similar time to optimal therapy and LOS. In the PoI, antimicrobial stewardship program (ASP) interventions were made significantly sooner after susceptibility results. CONCLUSION: In this small, retrospective, single-center study, the implementation of a rapid susceptibility testing method was associated with reduced time to susceptibility results and more rapid interventions by the ASP, but no difference in the rate of clinical failure or time to optimal therapy was identified. [Image: see text] [Image: see text] [Image: see text] DISCLOSURES: All authors: No reported disclosures.