Publication: Importancia de los plásmidos ColE1 en la resistencia a antibióticos
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2017-08-02
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Universidad Complutense de Madrid
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Abstract
Los antibióticos han salvado millones de vidas desde que en la década de 1940 se introdujeran en la práctica clínica. Desafortunadamente debido a la rápida aparición de resistencias, su fácil diseminación y la dificultad de su eliminación una vez que se han establecido en la población, nos encontramos ante un grave problema tanto para la salud humana como para la sanidad animal. Actualmente, se producen en torno a 700.000 muertes al año por bacterias resistentes a antibióticos, y se calcula que para 2050 se superarán las 10 millones asociadas a la resistencia a antibióticos. Los plásmidos juegan un papel determinante en la diseminación de la resistencia a antibióticos. Los plásmidos son moléculas de ADN que replican de forma independiente al cromosoma bacteriano y que tienen la capacidad de movilizar genes horizontalmente. En concreto, los plásmidos tipo ColE1 tienen una gran importancia en la resistencia a antibióticos. Estos pequeños replicones portan algunos determinantes de resistencia a los antibióticos más relevantes en la práctica clínica. Además son capaces de coexistir en una misma bacteria generando multirresistencia a varios antibióticos. Cuando una bacteria adquiere resistencia a antibióticos mediante la transferencia horizontal de un plásmido, compromete su crecimiento debido al coste biológico asociado al replicón. Esto genera que, en ausencia de presión selectiva, las bacterias que porten plásmidos serán menos competitivas comparado con las bacterias libres de replicones. Sin embargo, en presencia de antibióticos, las bacterias portando plásmidos serán seleccionadas en la población. La adaptación plásmido/hospedador es, por tanto, crucial para entender la presencia de los plásmidos portadores de resistencia en las poblaciones bacterianas...
Since their introduction in the 1940’s, antibiotics have saved millions of lives. Unfortunately, due to the rapid emergence and dissemination of resistance determinants combined with the difficulty of combatting resistance genes that have already been established within bacterial populations, we are now facing a grave problem both in human and animal health. Plasmids play a key role in the dissemination of antibiotic resistance genes. Plasmids are DNA molecules that replicate independently of the bacterial chromosome y have the ability to mobilize genes horizontally. ColE1-like plasmids, in particular, have a substantial impact on antibiotic resistance. These small replicons bear antibiotic resistance determinants against the most clinically relevant antibiotics. Furthermore, they are capable of coexisting in a single cell generating multiresistance to various antibiotics. When a bacterium acquires antibiotic resistance via plasmid mediated horizontal gene transfer, the bacterium compromises its fitness due to the biological cost incurred by the replicon. The biological cost, in absence of selective pressure, renders the bacteria bearing plasmids less competitive compared to the replicon-free bacteria. However, in the presence of antibiotic pressure, bacteria bearing plasmids will be selected for in the population. Elucidating the process of lasmid/host adaptation is therefore crucial to understand the presence of resistance-bearing plasmids in the bacterial populations...
Since their introduction in the 1940’s, antibiotics have saved millions of lives. Unfortunately, due to the rapid emergence and dissemination of resistance determinants combined with the difficulty of combatting resistance genes that have already been established within bacterial populations, we are now facing a grave problem both in human and animal health. Plasmids play a key role in the dissemination of antibiotic resistance genes. Plasmids are DNA molecules that replicate independently of the bacterial chromosome y have the ability to mobilize genes horizontally. ColE1-like plasmids, in particular, have a substantial impact on antibiotic resistance. These small replicons bear antibiotic resistance determinants against the most clinically relevant antibiotics. Furthermore, they are capable of coexisting in a single cell generating multiresistance to various antibiotics. When a bacterium acquires antibiotic resistance via plasmid mediated horizontal gene transfer, the bacterium compromises its fitness due to the biological cost incurred by the replicon. The biological cost, in absence of selective pressure, renders the bacteria bearing plasmids less competitive compared to the replicon-free bacteria. However, in the presence of antibiotic pressure, bacteria bearing plasmids will be selected for in the population. Elucidating the process of lasmid/host adaptation is therefore crucial to understand the presence of resistance-bearing plasmids in the bacterial populations...
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Tesis inédita de la Universidad Complutense de Madrid, Facultad de Veterinaria, Departamento de Sanidad Animal, leída el 20/12/2016