Distinct epidemiology and resistance mechanisms affecting ceftolozane/tazobactam in<i>Pseudomonas aeruginosa</i>isolates recovered from ICU patients in Spain and Portugal depicted by WGS

GES-13-CC235 and VIM type-CC175 were the most frequent MDR/XDR P. aeruginosa clones causing infections in Portuguese and Spanish ICU patients, respectively. Ceftolozane/tazobactam resistance was mainly due to carbapenemase production, although mutations in PBP-encoding genes may additionally be involved.