Molecular typing and genetic environment of the blaKPC gene in Chilean isolates of Klebsiella pneumoniae. (March 2016)

• Record Type: Journal Article
• Authors: Barría-Loaiza, Carla; Pincheira, Andrea; Quezada, Mario; Vera, Alejandra; Valenzuela, Pedro; Domínguez, Mariana; Lima, Celia A.; Araya, Ingrid; Araya, Pamela; Prat, Soledad; Aguayo, Carolina; Fernández, Jorge; Hormazábal, Juan Carlos; Bello-Toledo, Helia; González-Rocha, Gerardo
• Is Part Of: Journal of global antimicrobial resistance. Volume 4(2016:Mar.)
• Page Start: 28
• Page End: 34
• Publication Date: 2016-03
• Subjects: Klebsiella pneumoniae -- blaKPC -- KPC-24 -- Carbapenem resistance -- ST258 -- ST1161; Drug resistance -- Periodicals; Drug resistance -- Periodicals; Drug resistance; Periodicals; 616.9041
• DOI: 10.1016/j.jgar.2016.01.001
• Languages: English
• ISSNs: 2213-7165

Abstract

Highlights: 17 Klebsiella pneumoniae were found to display a multidrug-resistant phenotype. In 6 strains bla KPC was found to be probably located on a plasmid; however, in all cases there was no conjugal transfer. The genetic environment of bla KPC indicated that the gene was located in a genetic platform variant 1a in 11 isolates and in Tn 4401a in 6 isolates. This work describes a novel ST (ST1161) and the new variant KPC-24. Abstract: The aim of this work was to determine the genetic environment and transferability of bla KPC 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 bla KPC 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 bla KPC 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 bla KPC genetic environment revealed two distinct platforms, namely variant 1a and the Tn 4401a isoform, with the first being the most common (11/17 strains). Mating experiments failed to produce transconjugants; however, loss of bla KPC was achieved by plasmid curing in all assayed strains. In conclusion, in Chilean strains of K. pneumoniae, bla KPC 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.