Emergence of cefiderocol resistance during CZA treatment due to a large genomic deletion including ampD and piuCD genes in Pseudomonas aeruginosa

Here we report the emergence of in vivo cefiderocol resistance development in P. aeruginosa caused by a large genomic deletion including piuDC region in the absence of cefiderocol treatment. This deletion was likely selected by ceftazidime/avibactam treatment since also included the ampC regulator ampD, which is located close to the piuDC system.