Carbapenem-resistant Klebsiella pneumoniae are a major global threat in healthcare facilities. The propagation of carbapenem resistance determinants can occur through vertical transmission, with genetic elements being transmitted by the host bacterium, or by horizontal transmission, with the same genetic elements being transferred among distinct bacterial hosts. This work aimed to track carbapenem resistance transmission by K. pneumoniae in a healthcare facility. The study involved a polyphasic approach based on conjugation assays, resistance phenotype and genotype analyses, whole genome sequencing, and plasmid characterization by pulsed field gel electrophoresis and optical DNA mapping. Out of 40 K. pneumoniae clinical isolates recovered over two years, five were carbapenem- and multidrug-resistant and belonged to multilocus sequence type ST147. These isolates harboured the carbapenemase encoding blaKPC-3 gene, integrated in conjugative plasmids of 140 kbp or 55 kbp, belonging to replicon types incFIA/incFIIK or incN/incFIIK, respectively. The two distinct plasmids encoding the blaKPC-3 gene were associated with distinct genetic lineages, as confirmed by optical DNA mapping and whole genome sequence analyses. These results suggested vertical (bacterial strain-based) transmission of the carbapenem-resistance genetic elements. Determination of the mode of transmission of antibiotic resistance in healthcare facilities, only possible based on polyphasic approaches as described here, is essential to control resistance propagation.
Bibliographical noteFunding Information:
This work was supported by National Funding Agencies supporting the EuroNanoMed Joint Transnational Call project "Nanofluidics for ultrafast diagnosis of bacterial infections" (NanoDiaBac, ENMed/0001/2014): The Swedish Research Council, Sweden; Funda??o para a Ci?ncia e a Tecnologia (FCT), Portugal and by FEDER through project "Assessing the risks associated with environmental antibiotic resistant bacteria: propagation and transmission to humans" (PTDC/CTA-AMB/28196/2017) - Programa Operacional Competitividade e Internacionaliza??o, and by National Funds from FCT - Funda??o para a Ci?ncia e a Tecnologia. The authors acknowledge the FCT support provided by the host research centers, UID/Multi/50016/2019, UID/EQU/00511/ 2019 and "LEPABE-2-ECO-INNOVATION" - NORTE-01-0145- FEDER-000005 (Laboratory for Process Engineering, Environment, Biotechnology and Energy) funded by the European Regional Development Fund (ERDF), through COMPETE2020 - Programa Operacional Competitividade e Internacionaliza??o (POCI) and by national funds, through FCT - Funda??o para a Ci?ncia e a Tecnologia, and by Norte Portugal Regional Operational Programme (NORTE 2020), under PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). SKB has a personal grant from the Wenner-Gren foundation. CF has a Research Contract from the project PTDC/CTA-AMB/28196/.
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