Improving time-to-result: head-to-head comparison of three rapid AST systems for Gram-negative bacteremia, including the newly developed VITEK REVEAL.

Early antimicrobial susceptibility testing (AST) in Gram-negative (GN) bloodstream infections is critical to guide appropriate therapy. This study evaluated three rapid AST (RAST) systems-VITEK REVEAL, direct-from-blood-culture VITEK 2 (VITEK 2-RAST), and EUCAST disk diffusion (DD-RAST)-using 220 prospectively collected GN-positive blood cultures (GN-PBCs). A total of 18 GN species were tested, including IMPORTANCE: This study is the first to conduct a direct comparison of three rapid antimicrobial susceptibility testing (RAST) systems-VITEK REVEAL, VITEK 2-RAST, and DD-RAST-on a large, prospectively collected cohort of Gram-negative-positive blood cultures (GN-PBCs). The data offer valuable insights for laboratories evaluating RAST implementation, especially in EUCAST-based contexts. Among the systems tested, VITEK REVEAL stood out for its combination of rapid turnaround and high accuracy, including for antibiotic-resistant organisms and β-lactam/β-lactamase inhibitor (BL/BLI) antibiotics. These findings underscore the potential of RAST systems to deliver timely and reliable susceptibility results directly from GN-PBCs, thereby supporting more effective antimicrobial stewardship and clinical decision-making. However, the real-world impact will also depend on how well these systems integrate into routine workflows, as seamless implementation can directly affect time-to-result (TTR)-an essential element in optimizing the management of GN-bloodstream infection (BSI).