title: Dissemination of multiple drug resistance genes by class 1 integrons in Klebsiella pneumoniae isolates from four countries: a comparative study.
abstract: A comparative genetic analysis of 42 clinical Klebsiella pneumoniae isolates, resistant to two or more antibiotics belonging to the broad-spectrum β-lactam group, sourced from Sydney, Australia, and three South American countries is presented. The study focuses on the genetic contexts of class 1 integrons, mobilizable genetic elements best known for their role in the rapid evolution of antibiotic resistance among Gram-negative pathogens. It was found that the class 1 integrons in this cohort were located in a number of different genetic contexts with clear regional differences. In Sydney, IS26-associated Tn21-like transposons on IncL/M plasmids contribute greatly to the dispersal of integron-associated multiple-drug-resistant (MDR) loci. In contrast, in the South American countries, Tn1696-like transposons on an IncA/C plasmid(s) appeared to be disseminating a characteristic MDR region. A range of mobile genetic elements is clearly being recruited by clinically important mobile class 1 integrons, and these elements appear to be becoming more common with time. This in turn is driving the evolution of complex and laterally mobile MDR units and may further complicate antibiotic therapy.
authors.affiliation: The ithree Institute, University of Technology, Sydney 2007, Australia.
authors.forename: Piklu
authors.initials: P
authors.lastname: Roy Chowdhury
authors.forename: Ana
authors.initials: A
authors.lastname: Ingold
authors.forename: Natasha
authors.initials: N
authors.lastname: Vanegas
authors.forename: Elena
authors.initials: E
authors.lastname: Martínez
authors.forename: John
authors.initials: J
authors.lastname: Merlino
authors.forename: Andrea Karina
authors.initials: AK
authors.lastname: Merkier
authors.forename: Mercedes
authors.initials: M
authors.lastname: Castro
authors.forename: Gerardo
authors.initials: G
authors.lastname: González Rocha
authors.forename: Graciela
authors.initials: G
authors.lastname: Borthagaray
authors.forename: Daniela
authors.initials: D
authors.lastname: Centrón
authors.forename: Helia
authors.initials: H
authors.lastname: Bello Toledo
authors.forename: Carolina M
authors.initials: CM
authors.lastname: Márquez
authors.forename: H W
authors.initials: HW
authors.lastname: Stokes
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D016521:Electrophoresis, Gel, Pulsed-Field; D032023:Integrons / Q000235:genetics*; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction
chemical_list: D000900:Anti-Bacterial Agents