Whole-genome sequence analysis of cefiderocol-resistant E. coli and Klebsiella pneumoniae isolates from cefiderocol treatment-naïve patients

Cefiderocol (FDC) is regarded as a reserved therapeutic option for serious CRE infections. In an earlier study, we had reported a 9.9 % FDC resistance in CRE isolates. In the present study, we are reporting the whole genome sequencing analysis findings of two FDC-resistant CRE (One E. coli and one K. pneumoniae). PBP3 insertions and mutations in the siderophore receptor cirA were the primary drivers of FDC resistance in E. coli. In K. pneumoniae, there was intact porin and a single copy of blaNDM-5, and a combination of β-lactamase and carbapenem resistance genes, including blaTEM- 1B, blaCTX-M-15,blaNDM-5 and blaOXA-181.