Evaluation of gradient diffusion in vitro susceptibility testing of Aerococcus urinae.

Objective: Aerococcus urinae antimicrobial susceptibility testing can be performed via broth microdilution with Mueller-Hinton broth supplemented with lysed horse blood. We sought to compare this with the commonly used gradient diffusion method.

Methods: We compared broth microdilution with Mueller-Hinton broth supplemented with lysed horse blood and gradient diffusion via Mueller-Hinton agar supplemented with sheep blood for 190 A.