Performance of Direct Identification and EUCAST Rapid Antimicrobial Susceptibility Testing in Bloodstream Infections Using Sepsityper® and Disk Diffusion Methods

Background/Objectives: Rapid pathogen identification and targeted antimicrobial susceptibility testing (AST) in bloodstream infections are critical to reducing sepsis-related mortality. This study aimed to evaluate the performance of direct MALDI-TOF MS identification using the rapid Sepsityper® kit and to determine the diagnostic accuracy and reliability of the EUCAST Rapid Antimicrobial Susceptibility Testing (RAST) protocol at various incubation periods (4, 6, 8, and 16-20 h) from positive blood culture bottles.

Methods

A total of 71 clinical isolates recovered from positive blood cultures in the Medical Microbiology Laboratory of Ondokuz Mayıs University Faculty of Medicine were included. Samples prepared directly using the rapid Sepsityper® kit were identified via MALDI-TOF MS, while the EUCAST RAST protocol was simultaneously performed on Mueller-Hinton agar using disk panels guided by Gram stain results. Results were analyzed for Categorical Agreement (CA), major errors, and very major errors using routine automated AST data as the reference standard.