Publication: Enterococcus faecalis: nuevas perspectivas sobre la estructura poblacional y el impacto de los elementos genéticos móviles en la evolución
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2018-03-01
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Universidad Complutense de Madrid
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Abstract
Enterococcus faecalis es una especie bacteriana generalista que habita en una amplia variedad de hospedadores como mamíferos, reptiles insectos y aves, siendo la causa potencial de graves infecciones en todos ellos. Esta especie es también uno de los principales patógenos nosocomiales y uno de los mayores vehículos de transmisión de genes de resistencia a antibióticos. Para definir la estructura poblacional de E. faecalis es importante identificar las principales líneas clonales causantes de infecciones en hospedadores relevantes. Existen estudios basados en el análisis de datos de MLST mediante la aplicación de herramientas como eBURST (Based Upon Related Sequence Types) o BAPS (Análisis Bayesiano de la Estructura Poblacional) así como de cgMLST (Core Genome Multilocus sequencing), los cuales revelan una estructura epidémica con una alta tasa de recombinación/ mutación. Estos estudios destacan las dificultades para establecer una estructura poblacional y para elucidar la historia evolutiva de algunos de los linajes clonales. Además el limitado número de genomas provenientes de hospedadores no-humanos y las escasas herramientas para analizar especies con alta recombinación impide la confirmación de esta hipótesis. Estudiar cepas de animales salvajes es una buena aproximación para expandir el conocimiento disponible sobre la estructura poblacional de E. faecalis. Estos hospedadores están sometidos a una gran variedad de presiones selectivas (como antibióticos, metales pesados, biocidas u otros compuestos) y tienen una amplia red de contactos en los distintos ambientes que promueven el intercambio y el flujo entre diferentes comunidades bacterianas. Además, recientemente hemos creado nuevas herramientas en nuestro grupo y con los consorcios en los que participamos que nos permiten un estudio profundo del pangenoma de E. faecalis...
Enterococcus faecalis is a generalist bacterial species that inhabitant a variety of disparate hosts such as mammals, reptiles, insects and birds, being a potential cause of severe infections in all these hosts. This species is also one of the major nosocomial pathogens and antibiotic resistance threat. To define the structure of E. faecalis populations is important to identify main clonal lineages causing infections in relevant hosts. The available E. faecalis population structure reflects a cluster of a limited number of genotypes and a mismatch distribution dominated by mutation, with a slight increase of identical genotypes pairs due to local hospital transmission. The overrepresentation of E. faecalis isolates of hospitalized patients in gene databases precludes defining the population structure of those species colonizing different host organisms of poorly defined and disparate ecological patches. Most of the works published to date are based on MLST data analyzed by using goEBURST, Bayesian Analysis Population Structure (BAPS) software or cgMSLT and revealed an epidemic structure with a high recombination /mutation ratio. Such studies highlight the difficulties to establish the population structure and to elucidate the evolutionary history of some lineages. The limited number of genomes from non-human hosts and the tools to analyze species with a high recombination potential preclude confirming such hypothesis. Wild animals are a good subject for expanded the available knowledge on population structure of E. faecalis. They are subjected to a variety of selective pressures (antibiotics, heavy metals, biocides) and have a high rate of network of contacts promoting the exchange and flow between different bacterial communities. In addition, novel tools to analyse accessory genomes and typing mobile genetic elements developed in our group or the consortia in which we participated would allow a comprehensive search of the E. faecalis pan-genome...
Enterococcus faecalis is a generalist bacterial species that inhabitant a variety of disparate hosts such as mammals, reptiles, insects and birds, being a potential cause of severe infections in all these hosts. This species is also one of the major nosocomial pathogens and antibiotic resistance threat. To define the structure of E. faecalis populations is important to identify main clonal lineages causing infections in relevant hosts. The available E. faecalis population structure reflects a cluster of a limited number of genotypes and a mismatch distribution dominated by mutation, with a slight increase of identical genotypes pairs due to local hospital transmission. The overrepresentation of E. faecalis isolates of hospitalized patients in gene databases precludes defining the population structure of those species colonizing different host organisms of poorly defined and disparate ecological patches. Most of the works published to date are based on MLST data analyzed by using goEBURST, Bayesian Analysis Population Structure (BAPS) software or cgMSLT and revealed an epidemic structure with a high recombination /mutation ratio. Such studies highlight the difficulties to establish the population structure and to elucidate the evolutionary history of some lineages. The limited number of genomes from non-human hosts and the tools to analyze species with a high recombination potential preclude confirming such hypothesis. Wild animals are a good subject for expanded the available knowledge on population structure of E. faecalis. They are subjected to a variety of selective pressures (antibiotics, heavy metals, biocides) and have a high rate of network of contacts promoting the exchange and flow between different bacterial communities. In addition, novel tools to analyse accessory genomes and typing mobile genetic elements developed in our group or the consortia in which we participated would allow a comprehensive search of the E. faecalis pan-genome...
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Tesis inédita de la Universidad Complutense de Madrid, Facultad de Farmacia, Departamento de Microbiología II, leída el 06-07-2017