Evaluation of EUCAST rapid antimicrobial susceptibility test directly from positive blood culture for Pseudomonas aeruginosa

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 to 15.0%) and ME (ranging from 1.3 to 16.3%) after 6 h, particularly for key antibiotics such as ceftazidime, piperacillin/tazobactam, and meropenem. Extending the incubation time to 8 h may improve results (CA ranging from 87.2 to 99%), but caution is required in interpretation due to persistence of VME (ranging from 0.0 to 15.6%) and ME (ranging from 0.0 to 11.7%).