Clonal Spread and Intra- and Inter-Species Plasmid Dissemination Associated With Carbapenemase-Producing Enterobacterales During a Hospital Outbreak in Barcelona, Spain

The study aimed to characterize the clonal spread of resistant bacteria and dissemination of resistance plasmids among carbapenem-resistant Enterobacterales at a tertiary hospital in Catalonia, Spain. Isolates were recovered from surveillance rectal swabs and diagnostic samples. Species identification was by matrix-assisted laser desorption ionization-time time of flight mass spectrometry (MALDI-TOF MS). Molecular typing was performed by pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). Antimicrobial susceptibility was assessed by gradient-diffusion and carriage of genes was detected by PCR. Plasmid typing, conjugation assays, S1-PFGE studies and long-read sequencing were used to characterize resistance plasmids. From July 2018 to February 2019, 125 carbapenemase (KPC)-producing Enterobacterales were recovered from 101 inpatients from surveillance (74.4%) or clinical samples (25.6%), in a tertiary hospital in Barcelona. Clonality studies identified a major clone of belonging to sequence type ST15 and additional isolates of , and sp. from different STs. All isolates but one carried the allelic variant. The gene was located in an IncFIIk plasmid of circa 106 Kb in a non-classical Tn element designated NTE-pMC-2-1. Whole-genome sequencing revealed different rearrangements of the 106 Kb plasmid while the NTE-pMC-2-1 module was highly conserved. We report a hospital outbreak caused by the clonal dissemination of KPC-producing ST15 but also the intra- and inter-species transmission of the gene associated with plasmid conjugation and/or transposon dissemination. To our knowledge, this is the first report of an outbreak caused by KPC-producing Enterobacterales isolated from human patients in Catalonia and highlights the relevance of surveillance studies in the early detection and control of antibiotic resistant high-risk clones.