title: Molecular typing and genetic environment of the blaKPC gene in Chilean isolates of Klebsiella pneumoniae.
abstract: The aim of this work was to determine the genetic environment and transferability of blaKPC as well as the pulsotypes of KPC-producing Klebsiella pneumoniae strains isolated from clinical samples in Chilean hospitals. Seventeen strains, principally isolated in Santiago (the capital of Chile) during the years 2012 and 2013, were included. The genetic environment of blaKPC was elucidated by PCR mapping and sequencing. Molecular typing was performed by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Curing and conjugation experiments were performed with six strains of different sequence types (STs) and pulsotypes. Thirteen pulsotypes and six STs, mainly belonging to clonal complex 258, were found. In addition, seven strains belonged to a new ST assigned ST1161. The blaKPC sequence indicated that 16 strains had the KPC-2 variant; in only one strain (UC331) an amino acid change (R6P) was detected, corresponding to a new KPC variant designated KPC-24. Molecular characterisation of the blaKPC genetic environment revealed two distinct platforms, namely variant 1a and the Tn4401a isoform, with the first being the most common (11/17 strains). Mating experiments failed to produce transconjugants; however, loss of blaKPC was achieved by plasmid curing in all assayed strains. In conclusion, in Chilean strains of K. pneumoniae, blaKPC is primarily found associated with the variant 1a and is located in non-transferable plasmids. In addition, this study highlights the description of the new ST1161 and the new KPC-24 variant.
authors.affiliation: Laboratorio de Investigación en Agentes Antibacterianos, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile.
authors.forename: Carla
authors.initials: C
authors.lastname: Barría-Loaiza
authors.affiliation: Laboratorio de Investigación en Agentes Antibacterianos, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile.
authors.forename: Andrea
authors.initials: A
authors.lastname: Pincheira
authors.affiliation: Laboratorio de Investigación en Agentes Antibacterianos, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile.
authors.forename: Mario
authors.initials: M
authors.lastname: Quezada
authors.affiliation: Laboratorio de Investigación en Agentes Antibacterianos, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Vera
authors.affiliation: Laboratorio de Investigación en Agentes Antibacterianos, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile.
authors.forename: Pedro
authors.initials: P
authors.lastname: Valenzuela
authors.affiliation: Laboratorio de Investigación en Agentes Antibacterianos, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile.
authors.forename: Mariana
authors.initials: M
authors.lastname: Domínguez
authors.affiliation: Laboratorio de Investigación en Agentes Antibacterianos, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile.
authors.forename: Celia A
authors.initials: CA
authors.lastname: Lima
authors.affiliation: Departamento Laboratorio Biomédico Nacional y de Referencia, Instituto de Salud Pública de Chile, Santiago, Chile.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Araya
authors.affiliation: Departamento Laboratorio Biomédico Nacional y de Referencia, Instituto de Salud Pública de Chile, Santiago, Chile.
authors.forename: Pamela
authors.initials: P
authors.lastname: Araya
authors.affiliation: Departamento Laboratorio Biomédico Nacional y de Referencia, Instituto de Salud Pública de Chile, Santiago, Chile.
authors.forename: Soledad
authors.initials: S
authors.lastname: Prat
authors.affiliation: Departamento Laboratorio Biomédico Nacional y de Referencia, Instituto de Salud Pública de Chile, Santiago, Chile.
authors.forename: Carolina
authors.initials: C
authors.lastname: Aguayo
authors.affiliation: Departamento Laboratorio Biomédico Nacional y de Referencia, Instituto de Salud Pública de Chile, Santiago, Chile.
authors.forename: Jorge
authors.initials: J
authors.lastname: Fernández
authors.affiliation: Departamento Laboratorio Biomédico Nacional y de Referencia, Instituto de Salud Pública de Chile, Santiago, Chile.
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Hormazábal
authors.affiliation: Laboratorio de Investigación en Agentes Antibacterianos, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile. Electronic address: hbello@udec.cl.
authors.forename: Helia
authors.initials: H
authors.lastname: Bello-Toledo
authors.affiliation: Laboratorio de Investigación en Agentes Antibacterianos, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile.
authors.forename: Gerardo
authors.initials: G
authors.lastname: González-Rocha
mesh_terms: D015373:Bacterial Typing Techniques; D002677:Chile; D005798:Genes, Bacterial; D007710:Klebsiella Infections; D007711:Klebsiella pneumoniae / Q000235:genetics*; D058885:Multilocus Sequence Typing; D010957:Plasmids / Q000235:genetics; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D001618:beta-Lactamases
keywords: Carbapenem resistance; KPC-24; Klebsiella pneumoniae; ST1161; ST258; bla(KPC)