Emergence of cefiderocol resistance in Pseudomonas aeruginosa from a heteroresistant isolate

Cefiderocol is a siderophore cephalosporin designed to target multi-drug resistant Gram-negative bacteria. Previously, the emergence of cefiderocol non-susceptibility has been associated with mutations in the chromosomal cephalosporinase (PDC) along with mutations in the PirA and PiuA/D TonB dependent receptor pathways. The aim of this study was to assess the genomic changes associated with the emergence of cefiderocol resistance on therapy.