Evaluation of EUCAST Rapid Antimicrobial Susceptibility Test directly from positive blood culture for Pseudomonas aeruginosa 

Abstract In this study, we evaluated the performance of the EUCAST RAST method on a collection of 154 clinical strains of P. aeruginosa, including strains resistant to ceftazidime and carbapenems. While the test is convenient for routine laboratories, we observed significant rates of VME (ranging from 0.0–15.0%) and ME (ranging from 1.3–16.3%) after 6h, particularly for key antibiotics such as ceftazidime, piperacillin/tazobactam, and meropenem. Extending the incubation time to 8h may improve results (CA ranging from 87.2–99%), but caution is required in interpretation due to persistence of VME (ranging from 0.0–15.6%) and ME (ranging from 0.0–11.7%).