“IN VIVO EVALUATION OF THE EXCISION OF PATHOGENICITY ISLAND ROD21 OF Salmonella enterica serovar Enteritidis AND ITS ROLE IN THE REGULATION OF GENES EXPRESSION DURING THE DIFFERENT STAGES OF THE INFECTION CYCLE”
Pathogenicity islands excision is a mechanism that occurs in several Enterobacteriaceae family members, including Salmonella enterica subspecie enterica serovars. ROD21 is an excisable pathogenicity island present in the chromosome of Salmonella enterica serovar Enteritidis and other serovars. It ha...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2018 |
| País: | Chile |
| OAI Identifier: | oai:repositorio.anid.cl:10533/232956 |
| Acceso en línea: | https://hdl.handle.net/10533/232956 |
| Access Level: | acceso abierto |
| Palabra clave: | Ciencias Naturales Otras Ciencias Naturales |
| Sumario: | Pathogenicity islands excision is a mechanism that occurs in several Enterobacteriaceae family members, including Salmonella enterica subspecie enterica serovars. ROD21 is an excisable pathogenicity island present in the chromosome of Salmonella enterica serovar Enteritidis and other serovars. It has been described that excision of ROD21 may play an important role in the ability of S. Enteritidis to cause systemic infection in the murine model, because strain unable to excise ROD21 showed a reduced ability to colonize the liver and the spleen. In this work, the kinetics of ROD21 excision in vivo across the stages of the infective cycle performed by S. Enteritidis in C57BL/6 mice was evaluated and the importance of ROD21 excision on Salmonella infection ability and gene expression was determined. After different times post infection, bacterial load and excision frequency was quantified in different portions of the digestive tract and internal organs. It was observed that the frequency of ROD21 excision increased significantly in the bacterial population able to colonize mesenteric lymph nodes at early stages, remaining very low in liver and spleen during these stages. However, a drastic increase in ROD21 excision was observed at late times post infection when intestinal re-infection and mortality start to happen. These observations suggest that the inability to excise ROD21 affects the translocation of S. Enteritidis from the intestine to the mesenteric lymph nodes due, possibly, to a defect in its capacity to invade host cells. On the other hand, the assays showed that impairment to excise ROD21 can affect the expression of genes located both within and outside the island. These results may be indicating that ROD21´s excision is a genetic mechanism employed by S. Enteritidis to regulate the expression of its virulence genes, to adapt to the conditions found in different tissues and to produce a successful systemic infection in the mouse. |
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