title: Investigation of diversity of plasmids carrying the blaTEM-52 gene.
abstract: OBJECTIVE
  To investigate the diversity of plasmids that carry bla(TEM-52) genes among Escherichia coli and Salmonella enterica originating from animals, meat products and humans.
  
  
  METHODS
  A collection of 22 bla(TEM-52)-encoding plasmids was characterized by restriction fragment length polymorphism (RFLP), replicon typing (by PCR or replicon sequencing), susceptibility testing, assessment of plasmid ability to self-transfer by conjugation and typing of the genetic environment of the bla(TEM-52) gene. Detected IncI1 plasmids underwent further plasmid multilocus sequence typing.
  
  
  RESULTS
  RFLP profiles demonstrated dissemination of bla(TEM-52) in Denmark (imported meat from Germany), France, Belgium and the Netherlands from 2000 to 2006 by mainly two different plasmids, one encoding bla(TEM-52b) (IncX1A, 45 kb) and the other bla(TEM-52c) (IncI1, 80 kb). In addition, bla(TEM-52b) was also found to be located on various other plasmids belonging to IncA/C and IncL/M, while bla(TEM-52c) was found on IncN-like as well as on IncR plasmids. In the majority of cases (n = 21) the bla(TEM-52) gene was located on a Tn3 transposon. Seven out of 10 bla(TEM-52) plasmids tested in conjugation experiments were shown to be capable of self-transfer to a plasmid-free E. coli recipient.
  
  
  CONCLUSIONS
  The bla(TEM-52) gene found in humans could have been transmitted on transferable plasmids originating from animal sources. Some of the bla(TEM-52) plasmids carry replicons that differ from the classical ones. Two novel replicons were detected, IncX1A and IncN-like. Unlike its predecessor bla(TEM-1), the bla(TEM-52) gene was not detected on F-type replicons suggesting that this gene evolved on other types of plasmid scaffolds.
authors.affiliation: National Food Institute, Technical University of Denmark, Kemitorvet 204, 2800 Kongens Lyngby,  Denmark.
authors.forename: Eliza
authors.initials: E
authors.lastname: Bielak
authors.forename: Rikke D
authors.initials: RD
authors.lastname: Bergenholtz
authors.forename: Mikael Skaanning
authors.initials: MS
authors.lastname: Jørgensen
authors.forename: Søren J
authors.initials: SJ
authors.lastname: Sørensen
authors.forename: Lars H
authors.initials: LH
authors.lastname: Hansen
authors.forename: Henrik
authors.initials: H
authors.lastname: Hasman
mesh_terms: D000818:Animals; D004251:DNA Transposable Elements / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification; D005060:Europe; D022761:Gene Transfer, Horizontal; D014644:Genetic Variation; D006801:Humans; D008826:Microbial Sensitivity Tests; D058885:Multilocus Sequence Typing; D010957:Plasmids / Q000302:isolation & purification; D012150:Polymorphism, Restriction Fragment Length; D019779:Salmonella enterica / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification; D019895:Transposases / Q000235:genetics; D018440:beta-Lactam Resistance / Q000235:genetics; D001618:beta-Lactamases / Q000235:genetics*; D047090:beta-Lactams / Q000494:pharmacology
chemical_list: D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D047090:beta-Lactams; C473502:Tn3 transposase; D019895:Transposases; C445691:TEM-52 beta-lactamase; D001618:beta-Lactamases