A megaplasmid family driving dissemination of multidrug resistance in Pseudomonas.

Multidrug resistance (MDR) represents a global threat to health. Here, we used whole genome sequencing to characterise Pseudomonas aeruginosa MDR clinical isolates from a hospital in Thailand. Using long-read sequence data we obtained complete sequences of two closely related megaplasmids (>420 kb) carrying large arrays of antibiotic resistance genes located in discrete, complex and dynamic resistance regions, and revealing evidence of extensive duplication and recombination events.

Genetic environment of metallo-β-lactamase genes in Pseudomonas aeruginosa isolates from the UK.

Objectives: We sought to characterize the genetic environment of blaVIM and blaIMP genes in Pseudomonas aeruginosa isolates from the UK; these included members of six previously described prevalent complexes, A-F, which correspond to international 'high-risk clones', along with diverse strains.

Methods: Metallo-β-lactamase (MBL)-encoding class 1 integrons were amplified by PCR from 218 P. aeruginosa isolates producing VIM-type (n = 196) or IMP-type (n = 22) enzymes, referred from UK hospital laboratories between 2003 and 2012.

Dominance of international 'high-risk clones' among metallo-β-lactamase-producing Pseudomonas aeruginosa in the UK.

Objectives: Carbapenem-resistant isolates of Pseudomonas aeruginosa producing metallo-β-lactamases (MBLs) are increasingly reported worldwide and often belong to particular 'high-risk clones'. This study aimed to characterize a comprehensive collection of MBL-producing P. aeruginosa isolates referred to the UK national reference laboratory from multiple UK laboratories over a 10 year period.