Two decades of blaVIM-2-producing Pseudomonas aeruginosa dissemination: an interplay between mobile genetic elements and successful clones.

Objectives: Information on clonal lineages and genetic platforms involved in the mobilization of carbapenemases between Pseudomonas aeruginosa strains in Portugal is scarce. Here, we outline the genetic drivers contributing to the occurrence of blaVIM-2-producing P. aeruginosa over two decades.

Methods: A collection of carbapenem-resistant P. aeruginosa clinical isolates (n = 263, 1995-2014) was screened for carbapenemase production by Blue-Carba and PCR. Antimicrobial susceptibility testing was performed according to EUCAST and clonal analysis by MLST. Nine isolates representing different integrons and STs were selected for WGS, followed by bioinformatics.

Results: Twenty-seven blaVIM-2-producing P. aeruginosa belonging to 10 STs were identified, with ST179 and ST111 being the most prevalent and persistent clones. blaVIM-2 was associated with seven class I integrons frequently co-harbouring aminoglycoside resistance genes. In58 was commonly identified, followed by derivatives and In100. blaVIM-2-harbouring transposons of the Tn3 and Tn402 families were linked to different plasmids or integrative conjugative elements of the clc family.

Conclusions: The dissemination of blaVIM-2 carrying integrons is associated with a complex interplay between different mobile genetic elements, including the overlooked integrative conjugative elements, and successful spread of particular clones.