Background: A carbapenem-resistant Escherichia coli  (sequence type 5415) strain was isolated from a male patient through routine surveillance in 2018 in Guangzhou, China.
Materials and Methods: Bacteria were isolated from a sputum culture and identified by using the Vitek 2 compact system. The bla_NDM-5  gene was amplified and confirmed by sequencing. Antimicrobial susceptibility testing was determined by a Vitek 2 compact system. The bla_NDM-5  gene was located by Southern blotting. Whole-genome sequencing was carried out using both Illumina MiSeq and Oxford Nanopore MinION.
Results: S1-PFGE and Southern blotting showed that the bla _NDM-5 gene was located on a novel 66-kb IncFII [F2:A-:B-] plasmid. Conjugation assays revealed that the bla _NDM-5-bearing plasmid was self-transferrable. Genomic sequencing and comparative analysis suggested that plasmid p2947-NDM5 likely originated from a combination of an IncFII-type backbone and the bla _NDM-5 flanking genetic elements.
Conclusion: This is the first report of an ST5414 E. coli  strain expressing an NDM-5 β-lactamase. This study highlights the genetic complexity of bla _NDM-5 carrying plasmids and the urgent need for continuous active monitoring.
Keywords: Escherichia coli , ST5415, NDM-5, IncFII, carbapenem resistant