title: Dispersal of carbapenemase blaVIM-1 gene associated with different Tn402 variants, mercury transposons, and conjugative plasmids in Enterobacteriaceae and Pseudomonas aeruginosa.
abstract: The emergence of bla(VIM-1) within four different genetic platforms from distinct Enterobacteriaceae and Pseudomonas aeruginosa isolates in an area with a low prevalence of metallo-beta-lactamase producers is reported. Forty-three VIM-1-producing isolates (including 19 Enterobacter cloacae, 2 Escherichia coli, and 2 P. aeruginosa isolates, 18 Klebsiella pneumoniae isolate, and 2 Klebsiella oxytoca isolate) recovered from 2005 to 2007 and corresponding to 15 pulsed-field gel electrophoresis types were studied. The Enterobacteriaceae isolates corresponded to a hospital outbreak, and the P. aeruginosa isolates were sporadically recovered. The genetic context of the integrons carrying bla(VIM-1) (arbitrarily designated types A, B, C, and D) was characterized by PCR mapping based on known Tn402 and mercury transposons and further sequencing. Among Enterobacteriaceae isolates, bla(VIM-1) was part of integrons located either in an In2-Tn402 element linked to Tn21 (type A; In110-bla(VIM-1)-aacA4-aadA1) or in a Tn402 transposon lacking the whole tni module [type B; In113-bla(VIM-1)-aacA4-dhfrII (also called dfrB1)-aadA1-catB2] and the transposon was associated with an IncHI2 or IncI1 plasmid, respectively. Among P. aeruginosa isolates, bla(VIM-1) was part of a new gene cassette array located in a defective Tn402 transposon carrying either tniBDelta3 and tniA (type C; bla(VIM-1)-aadA1) or tniC and DeltatniQ (type D; bla(VIM-1)-aadB), and both Tn402 variants were associated with conjugative plasmids of 30 kb. The dissemination of bla(VIM-1) was associated with different genetic structures and bacterial hosts, depicting a complex emergence and evolutionary network scenario in our facility, Ramón y Cajal University Hospital, Madrid, Spain. Knowledge of the complex epidemiology of bla(VIM-1) is necessary to control this emerging threat.
authors.affiliation: Servicio de Microbiología, Hospital Universitario Ramón y Cajal, Carretera de Colmenar, km. 9.1, Madrid 28034, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Tato
authors.forename: Teresa M
authors.initials: TM
authors.lastname: Coque
authors.forename: Fernando
authors.initials: F
authors.lastname: Baquero
authors.forename: Rafael
authors.initials: R
authors.lastname: Cantón
mesh_terms: D003001:Cloning, Molecular; D003227:Conjugation, Genetic / Q000235:genetics; D004251:DNA Transposable Elements / Q000187:drug effects / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D004755:Enterobacteriaceae / Q000187:drug effects* / Q000235:genetics*; D032023:Integrons / Q000235:genetics; D008628:Mercury / Q000494:pharmacology*; D009841:Oligonucleotides / Q000235:genetics; D010957:Plasmids / Q000187:drug effects / Q000235:genetics*; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000235:genetics*; D001618:beta-Lactamases / Q000235:genetics
chemical_list: D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D009841:Oligonucleotides; C417264:VIM-1 metallo-beta-lactamase; D001618:beta-Lactamases; D008628:Mercury