Comunicación oral en Seminarios VISAVET 2024

27 de junio de 2024

Garcillan MP.

Beyond their use as workhorses in molecular biology and biotechnology, plasmids are essential components of bacterial genomes. Plasmids facilitate the horizontal transfer of antibiotic resistance, virulence genes, and other adaptive traits among bacterial populations. We analyzed the genomic composition and pairwise sequence identity across more than 10,000 reference plasmids, generating a comprehensive map of the bacterial plasmidome. Within this map, plasmids formed distinct clusters, termed plasmid taxonomic units (PTUs), characterized by high average nucleotide identity among their members. This detailed map of the bacterial plasmidome allows for the identification of potential pathways for plasmid-mediated exchanges among bacteria. The objective existence of plasmid species serves as a guide to automatically provide valuable information on plasmid characteristics. We applied this tool to the analysis of the Salmonella plasmidome. Establishing the persistent genome of each PTU in this pathogen revealed the biological features that characterize each plasmid species. Each PTU displays a specific host distribution, ranging from plasmids restricted to a few Salmonella serovars to those capable of colonizing species from different phyla. We specifically focused on Salmonella Typhi and used a k-mer-based Jaccard Index analysis to compute pangenome (i.e., core and accessory) relatedness, and graphically express both vertical and horizontal evolutionary relationships in a reticulate network. This analysis revealed a non-random structure in the Typhi pangenome that is driven predominantly by the gain and loss of mobile genetic elements, confirming and expanding upon known epidemiological patterns, revealing novel plasmid dynamics, and identifying avenues for further genomic epidemiological exploration.

	Instituto de Biomedicina o Biotecnología de Cantabria (IBBTEC). Consejo Superior de Investigaciones Científicas (CSIC). Universidad de Cantabria (UC).
	Centro de Vigilancia Sanitaria Veterinaria (VISAVET). Universidad Complutense (UCM).

Enlace a Seminarios VISAVET 2024