title: Multilocus sequence typing of IncN plasmids.
abstract: OBJECTIVE
  Incompatibility group N (IncN) plasmids have been associated with the dissemination of antimicrobial resistance and are a major vehicle for the spread of bla(VIM-1) in humans and bla(CTX-M-1) in animals. A plasmid multilocus sequence typing (pMLST) scheme was developed for rapid categorization of IncN plasmids.
  
  
  METHODS
  Twelve fully sequenced IncN plasmids available at GenBank were analysed in silico for selecting the loci for the IncN-specific pMLST. A total of 58 plasmids originating from different reservoirs (human, pig, poultry, cattle and horses) and geographic regions (Italy, Greece, Denmark, UK and The Netherlands) were classified by DNA sequencing of the amplicons obtained for the repA, traJ and korA loci.
  
  
  RESULTS
  Eleven sequence types (STs) were defined on the basis of allele sequences of the three selected loci. Most plasmids carrying bla(CTX-M-1) (24/27) isolated in different countries from both animals and humans belonged to ST1, suggesting dissemination of an epidemic plasmid through the food chain. Fifteen of 17 plasmids carrying bla(VIM-1) from Klebsiella pneumoniae and Escherichia coli, isolated during a 5 year period in Greece were assigned to ST10, suggesting that spread and persistence of this particular IncN-carrying bla(VIM-1) lineage in Greece.
  
  
  CONCLUSIONS
  This study proposes the use of pMLST as a suitable and rapid method for identification of IncN epidemic plasmid lineages. The recent spread of bla(CTX-M-1) among humans and animals seems to be associated with the dissemination of an epidemic IncN plasmid lineage.
authors.affiliation: Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Aurora
authors.initials: A
authors.lastname: García-Fernández
authors.forename: Laura
authors.initials: L
authors.lastname: Villa
authors.forename: Arshnee
authors.initials: A
authors.lastname: Moodley
authors.forename: Henrik
authors.initials: H
authors.lastname: Hasman
authors.forename: Vivi
authors.initials: V
authors.lastname: Miriagou
authors.forename: Luca
authors.initials: L
authors.lastname: Guardabassi
authors.forename: Alessandra
authors.initials: A
authors.lastname: Carattoli
mesh_terms: D000818:Animals; D002417:Cattle; D004269:DNA, Bacterial / Q000145:classification / Q000235:genetics; D004197:Disease Reservoirs; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D005060:Europe; D020387:Food Chain; D006736:Horses; D006801:Humans; D007711:Klebsiella pneumoniae / Q000201:enzymology / Q000235:genetics; D008826:Microbial Sensitivity Tests; D058885:Multilocus Sequence Typing; D010957:Plasmids / Q000235:genetics*; D011200:Poultry; D040081:Protein Array Analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013552:Swine
chemical_list: D004269:DNA, Bacterial