Publication: Resistencia, virulencia y estructura poblacional de "Escherichia coli" uropatógeno
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2018-02-19
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Universidad Complutense de Madrid
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Abstract
E. coli es el principal causante de infecciones del tracto urinario a nivel comunitario y hospitalario. La mayoría de estas infecciones están causadas por E. coli uropatógeno (UPEC), un patotipo específico dentro de la población de E. coli patogénico extraintestinal (ExPEC). Numerosos estudios alertan de un incremento de la incidencia de sepsis de origen urinario causadas por E. coli multirresistente. Este incremento se ha asociado a la expansión mundial de un clon de alto riesgo, el clon E. coli-B2-ST131. Este clon presenta un gran número de factores de virulencia (FV) y los análisis de su estructura poblacional han mostrado que su expansión se debe a un linaje dentro de ST131 caracterizado por la expresión del alelo 30 de fimH. Este linaje se ha asociado a resistencia a quinolonas y engloba al subclón H30Rx, asociado a expresión de betalactamasas de espectro extendido (BLEEs), principalmente CTXM- 15. Los motivos del predominio del clon ST131 entre los aislados de E. coli UPEC no están bien esclarecidos y se postula que puede ser debido a ventajas adaptativas conferidas bien por su mayor número de FV que le permitirían colonizar o invadir con mayor eficacia o bien por ser resistente a múltiples familias de antibióticos. Esta tesis plantea la hipótesis de que tanto los FV como la resistencia a antibióticos están implicados en la diseminación del clon ST131. Para probar esta hipótesis, el objetivo principal de esta tesis fue describir la estructura poblacional y los determinantes de resistencia y virulencia de E. coli-ST131 en una población de aislados invasivos y no invasivos...
E. coli is the main agent of urinary tract infections in the community and hospital setting, mainly due to uropathogenic E. coli (UPEC), a specific pathotype found in the extraintestinal pathogenic E. coli (ExPEC) population. Several studies have alerted of a rise in the incidence of urinary sepsis due to multidrug-resistant E. coli. This increase has been associated with the worldwide expansion of a high-risk clone, the E. coli B2-ST131. This clone shows a high content in virulence factors (VFs) and population structure analyses have demonstrated that its expansion is due to a lineage characterized by the expression of the allele 30 of the fimH gene. This lineage has been associated to quinolones resistance and includes subclone H30Rx, associated with production of extended spectrum betalactamases (ESBL), mainly CTX-M-15. The reason for the predominance of clone ST131 among UPEC isolates is not clear and it is postulated that it may be due to adaptive advantages conferred either by its greater number of VF that would allow it to better colonize or invade the host or by it’s being resistantt to several families of antimicrobials. This thesis proposes the hypothesis that both the virulence factors and antimicrobial resistance are implicated in the dissemination of the ST131 clone. To prove this hypothesis, the main objective of this thesis was to describe the population structure and the virulence and resistance determinants of E. coli-ST131 in a population of invasive and non-invasive isolates...
E. coli is the main agent of urinary tract infections in the community and hospital setting, mainly due to uropathogenic E. coli (UPEC), a specific pathotype found in the extraintestinal pathogenic E. coli (ExPEC) population. Several studies have alerted of a rise in the incidence of urinary sepsis due to multidrug-resistant E. coli. This increase has been associated with the worldwide expansion of a high-risk clone, the E. coli B2-ST131. This clone shows a high content in virulence factors (VFs) and population structure analyses have demonstrated that its expansion is due to a lineage characterized by the expression of the allele 30 of the fimH gene. This lineage has been associated to quinolones resistance and includes subclone H30Rx, associated with production of extended spectrum betalactamases (ESBL), mainly CTX-M-15. The reason for the predominance of clone ST131 among UPEC isolates is not clear and it is postulated that it may be due to adaptive advantages conferred either by its greater number of VF that would allow it to better colonize or invade the host or by it’s being resistantt to several families of antimicrobials. This thesis proposes the hypothesis that both the virulence factors and antimicrobial resistance are implicated in the dissemination of the ST131 clone. To prove this hypothesis, the main objective of this thesis was to describe the population structure and the virulence and resistance determinants of E. coli-ST131 in a population of invasive and non-invasive isolates...
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Tesis inédita de la Universidad Complutense de Madrid, Facultad de Farmacia, Departamento de Microbiología , leída el 30-05-2017