<p>Identification of <em>fosA10</em>, a Novel Plasmid-Mediated Fosfomycin Resistance Gene of <em>Klebsiella pneumoniae</em> Origin, in <em>Escherichia coli</em></p>

Abstract

Purpose: Several subtypes of plasmid-mediated fosfomycin resistance gene fosA in Enterobacteriaceae have been reported worldwide and have caused concern. The present study characterized a novel member of fosA gene located on a plasmid from Escherichia coli. Materials and Methods: A fosfomycin-resistant E. coli isolate PK9 was recovered from a chicken meat sample in 2018. The presence of fosA 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 fosA variant. Results: A novel fosA gene with significant homology (>98%) with fosA6 and fosA5 genes was identified by WGS and was named fosA10. FosA10 shared 56.1% to 98.6% amino acid sequence identity with other reported plasmid-mediated FosA enzymes. Fosfomycin resistance and fosA10 gene were successfully transferred to E. coli C600 by conjugation. Cloning confirmed that FosA10 could confer fosfomycin resistance (MIC > 128 μg/mL). The fosA10 gene was localized on a 53kb IncFII (F35:A-:B-) plasmid. The ΔlysR-fosA10-Δhp fragment (4328 bp), located between two copies of IS10R, showed 100% identity with the chromosomal sequences of 17 Klebsiella pneumoniae strains of ST664 and one of ST3821 in GenBank. Conclusion: Our findings indicated that the fosA10 gene of E. coli might be captured from the chromosome of K. pneumoniae by IS10, which further demonstrated that K. pneumoniae might act as a reservoir of fosA-like genes acquired by E. coli.

A Conjugative IncI1 Plasmid Carrying erm (B) and bla CTX-M-104 That Mediates Resistance to Azithromycin and Cephalosporins

“…No mobile genetic elements were found surrounding the fosA gene. However, the fosA gene from the chromosome of K. pneumoniae can be captured by E. coli and disseminated through mobile elements ( 13 ).…”

Mobile fosfomycin resistance genes in Enterobacteriaceae—An increasing threat

“…The highly similar fosA5 , fosA6 , and fosA10 genes (less than 10 nucleic acid sequence differences) were proposed to originate from the K . pneumoniae chromosome (Guo et al, 2016; Huang et al, 2020; Ma et al, 2015). In all three genes, lysR genes truncated by IS 10 were present upstream of the fosA gene.…”

“…In all three genes, lysR genes truncated by IS 10 were present upstream of the fosA gene. The downstream fragments of fosA5 , fosA6 , and fosA10 varied thus separate mobilization events of fosA KP were likely (Guo et al, 2016; Huang et al, 2020; Ma et al, 2015).…”

Multiple Plasmid Vectors Mediate the Spread of fosA3 in Extended-Spectrum-β-Lactamase-Producing Enterobacterales Isolates from Retail Vegetables in China

“…However, in recent years, many reports have described the presence of plasmidmediated fosfomycin resistance (fos) genes in Enterobacterales isolates around the world (5)(6)(7). The fosA gene is the most common of the plasmid-mediated fosfomycin resistance genes in Enterobacterales, and 10 fosA gene types have been identified (7,8). Among them, fosA3 is the most frequently gene type and is disseminated mainly in Asian countries (China, South Korea, and Japan) but is detected in countries outside Asia only sporadically (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15).…”

“…The fosA gene is the most common of the plasmid-mediated fosfomycin resistance genes in Enterobacterales, and 10 fosA gene types have been identified (7,8). Among them, fosA3 is the most frequently gene type and is disseminated mainly in Asian countries (China, South Korea, and Japan) but is detected in countries outside Asia only sporadically (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15). The plasmid-borne fosA3 gene likely originated from the chromosome of Kluyvera georgiana (16) and has been detected in several Enterobacterales species such as Escherichia, Klebsiella, Salmonella, Proteus, and Citrobacter spp.…”