Dissemination of multiple drug resistance genes by Class 1 integrons in Klebsiella pneumoniae isolates from four countries: A comparative study.

CHOWDHURY PR, INGOLD A, VANEGAS N, MARTÍNEZ ME, MERLINO J, MERKIER AK, CASTRO M, GONZÁLEZ ROCHA G, BORTHAGARAY G, CENTRÓN D, TOLEDO HB, MÁRQUEZ CM, STOKES HW.

ANTIMICROBIAL AGENTS AND CHEMOTHERAPY

AMER SOC MICROBIOLOGY

Lugar: Washington DC; Año: 2011 vol. 55 p. 3140 - 3149

0066-4804

We present a comparative analysis of 42 clinical multiple drug resistance (MDR) Klebsiella pneumoniae, isolated from Sydney and three South American countries (Chile, Argentina, Uruguay), with a focus on the genetic contexts of class 1 integrons; a mobile genetic element predominantly implicated in the spread of antibiotic resistance in Gram-negative pathogens. High level of context diversity was identified, with a clear trend towards regional differences. In Sydney, IS26 associated Tn21-like transposons on IncL/M plasmid/s appeared to be the major dispersal units of class 1 integrons, in general. While in the South American countries, Tn1696-like transposons on IncA/C plasmid/s were involved in the dissemination of a ‘characteristic’ class 1 integron-associated MDR locus. A range of mobile elements are clearly being recruited by the clinically important ‘mobile integrons’ at an ever-accelerating rate, leading to changes in the basic components, so far know to be the ‘defining structural features’ of clinical class 1 integrons. Consequently distinct, complex and laterally mobile MDR-regions are evolving rapidly within pathogenic bacteria.