Comparative evaluation of agar dilution and Etest against broth microdilution for ceftobiprole susceptibility testing in methicillin-resistant Staphylococcus aureus: A multicentre study in China

This study demonstrates frequent clustering of MRSA isolates within the EUCAST-defined area of technical uncertainty, defined for ceftobiprole as an MIC of 2 mg/L, corresponding to the susceptibility breakpoint and its adjacent zone, where categorization is inherently unreliable. Methodological limitations of AD and Etest further increase the risk of misclassification and potential failure to detect resistance. These findings underscore the need for optimized susceptibility testing strategies and refined interpretive guidance to support accurate clinical use of ceftobiprole.