Identification of fosA10 , a Novel Plasmid-Mediated Fosfomycin Resistance Gene of Klebsiella pneumoniae Origin, in Escherichia coli

Several subtypes of plasmid-mediated fosfomycin resistance gene in have been reported worldwide and have caused concern. The present study characterized a novel member of gene located on a plasmid from . A fosfomycin-resistant isolate PK9 was recovered from a chicken meat sample in 2018. The presence of genes was detected by PCR and sequencing. Whole-genome sequencing (WGS), conjugation, and cloning were performed to identify the mechanism responsible for fosfomycin resistance. Oxford Nanopore MinION sequencing was carried out to characterize the plasmid carrying fosfomycin resistance gene and the genetic context of the novel variant. A novel gene with significant homology (>98%) with and genes was identified by WGS and was named . FosA10 shared 56.1% to 98.6% amino acid sequence identity with other reported plasmid-mediated FosA enzymes. Fosfomycin resistance and gene were successfully transferred to C600 by conjugation. Cloning confirmed that FosA10 could confer fosfomycin resistance (MIC > 128 μg/mL). The gene was localized on a 53kb IncFII (F35:A-:B-) plasmid. The fragment (4328 bp), located between two copies of IS10R, showed 100% identity with the chromosomal sequences of 17 strains of ST664 and one of ST3821 in GenBank. Our findings indicated that the gene of might be captured from the chromosome of by IS , which further demonstrated that might act as a reservoir of -like genes acquired by .