Characterisation of blaharbouring plasmids recovered from Pseudomonas aeruginosa ST654 and ST235 high-risk clones.

Objective: The main objectives were to describe two bla plasmids recovered from Pseudomonas aeruginosa isolates belonging to the ST654 and ST235 high-risk clones, and to compare with complete sequences of bla harbouring plasmids available in public databases.

Methods: Antimicrobial susceptibility was determined according to CLSI (Clinical and Laboratory Standards Institute) guidelines. Genomes were sequenced using an Illumina MiSeq platform, and bla plasmid sequences were achieved using MinION platform. Sequences were analysed using Unicycler and RAST. In silico predictions of the isolates sequence type (ST), antimicrobial resistance genes, plasmid replicon typing and MOB relaxases were fulfilled using bioinformatics tools.

Results: PA_2047 and PA_HdC isolates corresponded to the high-risk clones ST654 and ST235, respectively. The carbapenem resistance was mediated by KPC-2. Both bla harbouring plasmids, pPA_2047 and pPA_HdC, were different among them, non-conjugative and untypable by PlasmidFinder. pPA_2047 presented high identity with a Pae-13 plasmid, and these both located bla in Tn4401b isoform. pPA_HdC displayed a novel architecture, and the genetic context of bla was original. Besides the bla gene, resistance genes to aminoglycosides and quinolones were detected, including the novel phosphotransferase CrpP in PA_HdC.

Conclusion: This study expands the limited knowledge about the molecular epidemiology of bla in P. aeruginosa from Latin America. Two novel plasmids harbouring bla were described that were untypable by their incompatibility group. The plasmid recovered from P. aeruginosa PA_HdC (ST235) displayed a novel architecture and an original context for bla. On the other hand, the genetic platform carrying bla in P. aeruginosa PA_2047 (ST654) seems to a be a classical one.