title: Molecular Characterization of an Atypical IncX3 Plasmid pKPC-NY79 Carrying bla KPC-2 in a Klebsiella pneumoniae.
abstract: The IncX family of plasmids has recently been expanded to include at least four subtypes, IncX1-IncX4. The revised classification provides an opportunity for improving our understanding of the sequence diversity of the IncX plasmids and the resistance genes they carried. We described the complete nucleotide sequence of a novel IncX3 plasmid, pKPC-NY79 (42,447 bp) from a sequence-type 258 Klebsiella pneumoniae strain that was isolated from a patient who was hospitalized in New York, United States. In pKPC-NY79, the plasmid scaffold and genetic load region were highly similar to homologous regions in pIncX-SHV (IncX3, JN247852) and the bla KPC carrying pKpQIL (IncFIIk, GU595196), respectively, indicating that it has possibly arisen through recombination of plasmids. The bla KPC-2 gene, as part of a transposon Tn4401a, was found within the genetic load region. The backbone of pKPC-NY79 differs from pIncX-SHV by a deletion involving the gene tandem hns-topB (encoding H-NS protein and topoisomerase III, respectively) and a putative ATPase gene. Unexpectedly, the impact of the hns-topB deletion on host fitness and plasmid stability was found to be small. In conclusion, the findings contribute to a better understanding of the plasmid platforms carrying bla KPC and of variations in the backbone of the IncX3 plasmids.
authors.affiliation: Department of Microbiology, Queen Mary Hospital and Carol Yu Centre for Infection, The University of Hong Kong, China. plho@hkucc.hku.hk
authors.forename: Pak-Leung
authors.initials: PL
authors.lastname: Ho
authors.forename: Yuk-Yam
authors.initials: YY
authors.lastname: Cheung
authors.forename: Wai-U
authors.initials: WU
authors.lastname: Lo
authors.forename: Zhen
authors.initials: Z
authors.lastname: Li
authors.forename: Kin-Hung
authors.initials: KH
authors.lastname: Chow
authors.forename: Chi-Ho
authors.initials: CH
authors.lastname: Lin
authors.forename: Jasper Fuk-Woo
authors.initials: JF
authors.lastname: Chan
authors.forename: Vincent Chi-Chung
authors.initials: VC
authors.lastname: Cheng
mesh_terms: D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D004251:DNA Transposable Elements; D006801:Humans; D007710:Klebsiella Infections / Q000382:microbiology*; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification; D008297:Male; D010957:Plasmids / Q000235:genetics* / Q000378:metabolism; D014556:Urine / Q000382:microbiology; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D001618:beta-Lactamases