Rod21 excisión and its impact on the salmonella enteritidis virulence
Salmonella enterica serovar Enteritidis (S. Enteritidis) is a Gram negativebacterium and the etiological agent of severa! foodbome diseases in humans. As formany other Enterobacteria, the complete genome of S Enteritidis has been sequencedand annotated. Comparative analysis has allowed the identific...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2012 |
| País: | Chile |
| Idioma: | inglés |
| OAI Identifier: | oai:repositorio.anid.cl:10533/184491 |
| Acceso en línea: | http://creativecommons.org/licenses/by-nc-nd/3.0/cl/ https://hdl.handle.net/10533/184491 |
| Access Level: | acceso abierto |
| Sumario: | Salmonella enterica serovar Enteritidis (S. Enteritidis) is a Gram negativebacterium and the etiological agent of severa! foodbome diseases in humans. As formany other Enterobacteria, the complete genome of S Enteritidis has been sequencedand annotated. Comparative analysis has allowed the identification of several geneticregions absent in the genome of other Salmonella serovars, which have beendenominated "Regions OfDifference" (ROD). One ofthese regions is ROD21, which is flanked by direct repeated DNA sequences and harbors genes involved in virulence and genes encoding an integrase and an excisionase. We have demonstrated that ROD21 is an unstable genetic element, which is able of excise from the chromosome either under laboratory growth conditions or during infection of murine cells.Interestingly, we have observed that S Enteritidis strains lacking ROD21 show reduced virulence in mice.In this study we evaluated whether excision of ROD21 is required for S. Enteritidis to cause a systemic disease in its host. We generated mutant strains of S. Enteritidis lacking the direct repeated DNA sequence andlor an integrase, thus creatingstrains unable to excise this pathogenicity island and found that strains infecting micehad reduced capacity to cause a lethal disease and to colonize the spleen and liver, as compared with wild type S. Enteritidis. On the other hand, we observed that S. Enteritidis strains that overexpress an excisionase gene increased the frequency ofROD21 excision and showed increased ability to cause lethal disease in mice. Also,changes in the excision frequency ofROD21 shows changes in the expression of some genes contained therein. Our results suggest that excision of the pathogenicity islandROD21 in S. Enteritidis affects the capacity of this bacterium to cause disease in mi ce.These results suggest that the excision of ROD21 has an important role in modulatingthe virulence of S. Enteritidis. |
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