Klebsiella pneumoniaeis one of the main bacteria that cause infections in health care settings. This pathogen has developed a high level of resistance to many antibiotics.

The main objectives were to describe two bla_KPC-2 plasmids recovered from Pseudomonas aeruginosa isolates belonging to the ST654 and ST235 high-risk clones, and to compare with complete sequences of bla_KPC-2 harbouring plasmids available in public databases. Antimicrobial susceptibility was determined according to CLSI (Clinical and Laboratory Standards Institute) guidelines. Genomes were sequenced using an Illumina MiSeq platform, and bla_KPC-2 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. 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_KPC-2 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_KPC-2 in Tn4401b isoform. pPA_HdC displayed a novel architecture, and the genetic context of bla_KPC-2 was original. Besides the bla_KPC-2 gene, resistance genes to aminoglycosides and quinolones were detected, including the novel phosphotransferase CrpP in PA_HdC. This study expands the limited knowledge about the molecular epidemiology of bla_KPC-2 in P. aeruginosa from Latin America. Two novel plasmids harbouring bla_KPC-2 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_KPC-2. On the other hand, the genetic platform carrying bla_KPC-2 in P. aeruginosa PA_2047 (ST654) seems to a be a classical one.

To the best of our knowledge, no genomic descriptions of bla_VIM-11-harbouring plasmids are available in literature so far. The aim of this study was to describe the genomic features of three bla_VIM-11-harbouring plasmids recovered from Pseudomonas aeruginosa isolated in Argentina in different periods. bla_VIM-11-harbouring plasmids from three clinical P. aeruginosa isolates were transferred by transformation into P. aeruginosa PAO-1. Then, genomic DNA of these transformants was extracted and sequenced using NovaSeq 6000 System-Illumina. De novo assemblies were generated using Unicycler program and reads were mapped against a reference genome of P. aeruginosa PAO-1. Plasmids sequences were predicted identifying the reads that did not map the reference sequence of PAO-1. These reads were recovered and assembled de novo. In silico predictions were carried out using bioinformatics tools. One Plasmid (pP6VIM-11) was distributed in 2 contigs, a second plasmid (pPOta2VIM-11) was found in a single contig, and the last one (pP936401VIM-11) was fragmented into 4 contigs. pP6VIM-11 and pPOta2VIM-11 belonged to the IncP-1β group, displaying 64% of coverage and 83.9% of identity among them. pP936401VIM-1 plasmid corresponded to the IncN group. The bioinformatic analysis revealed that bla_VIM-11 was located in a class 1 integron, flanked by insertion sequences, exhibiting potential for its dissemination. However, none of the plasmids were conjugative. This study corresponded to the first description and deposit of bla_VIM-11-harbouring plasmids in P. aeruginosa, which expands the limited knowledge about their molecular epidemiology.

To describe at genomic level nine carbapenemase-producing Klebsiella pneumoniae ST307 (Kp-ST307) clinical isolates recovered in Buenos Aires during 2017 to 2021, investigating their resistome, virulome, and phylogeny. Antimicrobial susceptibility was determined according to Clinical and Laboratory Standards Intitute (CLSI). Genomic DNA was sequenced by Illumina MiSeq and analysed using SPAdes, PROKKA, and Kleborate. Phylogeny of 355 randomly selected Kp-ST307 genomes and those from nine local isolates was inferred by a maximum-likelihood approach. The tree was visualized using Microreact. Besides resistance to ß-lactams and fluoroquinolones, six out of nine Kp-ST307 were also resistant to ceftazidime/avibactam (CZA). This difficult-to-treat resvistance phenotype was mediated by bla_SHV-28 and GyrA-83I/ParC-80I mutations in addition to carbapenemase coding genes. Among CZA susceptible isolates, two of them harboured bla_KPC-3 while the other harboured bla_KPC-2+bla_CTX-M-15. Regarding CZA-resistant isolates, three harboured bla_KPC-3+bla_NDM-1+bla_CMY-6, two carried bla_KPC-2+bla_NDM-5+bla_CTX-M-15, and bla_NDM-5+bla_CTX-M-15 were detected in the remaining isolate. Furthermore, five colistin-resistant isolates presented a nonsense mutation in mgrB. Global Kp-ST307 isolates were distributed in two deep-branching lineages while local isolates were set in the main clade of the phylogenetic tree. The five isolates from the same hospital, harbouring bla_KPC-3 or bla_KPC-3+bla_NDM-1+bla_CMY-6, clustered in a monophyletic subclade with Italian isolates. Also, an isolate harbouring bla_KPC-2+bla_NDM-5+bla_CTX-M-15 recovered in another hospital was closed to this group. The remaining local Kp-ST307 were grouped in other subclades containing isolates of diverse geographical origin. The inferred resistome was consistent with the resistant phenotype. Phylogeny suggested multiple introduction events in our region and a single major introduction in one hospital followed by local spread.

Objective: To characterise four blaNDM-5 -harbouring plasmids recovered in Enterobacterales isolated in Argentina. Methods: DNA was sequenced by Illumina and Oxford Nanopore Technologies, assembled using Unicycler, analysed using PlasmidFinder, MOB-Typer, IslandViewer4, and Resfinder, and visualised by Proksee and Clinker. blaNDM-5 -harbouring plasmids were compared with similar deposited plasmids using PLSDB. Results: Two plasmids belonged to incompatibility group IncFII where blaNDM-5 was located in a previously described genetic context, immersed in an antimicrobial resistance island (ARI). Local IncFII plasmids displayed high similarity ( >= 90% shared hashes (sh)), with four deposited in PLSDB. The other two local plasmids belonged to the multi-replicon group IncFIB-HI1B, harbouring blaNDM-5 in a novel variant of the genetic context. Both multi-replicon plasmids presented two ARIs, one containing blaNDM-5 in addition to another antimicrobial resistance marker (ARM), and the second ARI carrying blaCTX-M-15 and a class 1 integron. Plasmids deposited in PLSDB showed low similarity to local multi-replicon plasmids. The most similar plasmids ( n = 5) displayed less than 60% shared hashes and showed the same Inc groups but lacked ARM. Conclusions: This study broadens the limited understanding of blaNDM-5 -harbouring plasmids in Latin America. Furthermore, it represents the first description of blaNDM-5 in a novel variant of common genetic platform and its location in multi-replicon IncFIB-IncHI1B plasmids, which were not previously associated with any ARM. (c) 2024 The Author(s). Published by Elsevier Ltd on behalf of International Society for Antimicrobial Chemotherapy. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )