180. Multicenter Analysis of Adequacy of Empiric and Definitive Therapy by Time to Culture Result in Hospitalized Patients with Blood Culture Positive for Carbapenem Resistant and Susceptible Enterobacterales and Pseudomonas aeruginosa

BACKGROUND: Rapid identification and antimicrobial susceptibility testing (AST) of pathogens causing bloodstream infections (BSI) is critical to providing accurate patient therapy. We conducted a multicenter evaluation of inadequate empiric (IET) and definitive therapy (IDT) from culture turn-around-time (TAT) in carbapenem susceptible (Carb-S) and carbapenem non-susceptible (Carb-NS) Enterobacterales (ENT) and P. aeruginosa (PSA) from blood specimens. METHODS: Hospitalized adults (≥ 18 yo) with facility reported AST from 2018-2022 across 161 facilities in the BD Insights Research Database (Franklin Lakes, NJ) were identified for non-contaminant Carb-S and Carb-NS ENT and PSA from blood specimens. We evaluated antibacterial therapy as IET (from culture collection to prior to first AST result) and IDT (48-hours post first AST result and not discharged) by 12-hour increments of culture TAT (date/time first AST results minus date/time culture collection). RESULTS: In total, we identified 42,125 ENT of which 1.2% (525) were Carb-NS, and 3,750 PSA of which 11.3% (423) were Carb-NS. The median time to AST results (hrs.) was significantly longer in Carb-NS ENT vs. Carb-S ENT (73.0 vs. 60.0) and in Carb-NS PSA vs. Carb-S PSA (77.8 vs. 69.5; Table 1). Average IDT was significantly lower than IET in Carb-S ENT (2.0% vs. 6.2%), Carb-NS ENT (15.1% vs. 45.6%), Carb-S PSA (3.6% vs. 10.8%) and Carb-NS PSA (14.6% vs. 39.8%) pathogen results. IDT was lower than IET at each 12-hour increment of availability of AST results (Figures 2, 3). IDT was also lower than IET at each 12-hour increment of availability of AST results for Carb-S ENT and Carb-NS ENT (Figure 2) and Carb-S PSA and Carb-NS PSA (Figure 3). Overall IDT was 15.1% and 14.6% in Carb-NS ENT and Carb-NS PSA, respectively, and only 2.0% and 3.6% in Carb-S ENT and Carb-S PSA, respectively. [Figure: see text] [Figure: see text] [Figure: see text] CONCLUSION: The time it takes to obtain a pathogen identification and AST results for Carb-NS ENT and PSA organisms is longer than Carb-S ENT and PSA organisms, resulting in Carb-NS patients remaining on IET for extended periods of time. Additionally, since a higher percentage of Carb-NS patients never receive adequate targeted therapy, efforts to integrate diagnostic and antimicrobial stewardship can improve both timing of culture results and receipt of adequate therapy. [Figure: see text] DISCLOSURES: Lauren Cooper, PhD, MPH, D(ABMM), AbbVie: Grant/Research Support|Becton Dickinson, Inc: Stocks/Bonds Kalvin Yu, MD, FIDSA, BD: Stocks/Bonds ChinEn Ai, MPH, Becton, Dickinson and Company: Employee Anuprita Patkar, PhD, BD: Grant/Research Support|BD: Stocks/Bonds Vikas Gupta, PharmD, Becton, Dickinson and Company (BD): Employee of BD|Becton, Dickinson and Company (BD): Stocks/Bonds