Bases moléculaires de la pathogénicité des Salmonella
In order to establish a successful infection, Salmonella must colonize host membranes, adhere to and invade epithelial cells, survive and even multiply in the reticuloendothelial system, produce tissue damages, and resist to host defence. Salmonella expresses virulence factors to fulfill these requirements. In S. typhi, the agent of human typhoid fever, all these factors are encoded by chromosomal genes. In S. typhimurium, the agent of murine typhoid fever, virulence factors are encoded by both chromosomal and plasmid genes. These factors, their functions and the genes involved in their synthesis and expression are covered in this review.
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ABSTRACT: The 90 kb virulence plasmid of Salmonella typhimurium is required for bacterial growth beyond the small intestine to deeper tissues such as the spleen and liver of orally inoculated mice. We constructed transcriptional lacZ fusions within the cloned plasmid-borne virulence genes spvA, spvB and spvC of S. typhimurium to demonstrate that spvR encodes a trans-acting positive regulator for the transcription of spvA, spvB and spvC. Data suggesting that the activation of spvABC transcription is dependent on the growth phase of both S. typhimurium and Escherichia coli grown in Luria Broth (LB) are also presented. Complementation experiments for virulence in mice confirmed that at least spvR and spvC are virulence genes and further suggested that the spvRABC gene cluster consists of at least three transcriptional units containing spvR, spvC and spvABC, respectively. Reinitiation of transcription at spvC was confirmed in vitro, using a lacZ fusion, and was shown to be independent of SpvR-mediated control in LB.
Microbial Pathogenesis 09/1992; 13(2):133-43. DOI:10.1016/0882-4010(92)90073-W · 1.79 Impact Factor
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ABSTRACT: A clinical collaborative study was conducted to compare two new chromogenic agar media, Rambach agar and the Salmonella Detection and Identification Medium (SMID) (bioMérieux, France), with two conventional media, Salmonella-Shigella agar and Hektoen agar. Thirty-nine Salmonella strains involving 14 serotypes were isolated from 1,454 stool specimens. After enrichment in a selective broth, 100% sensitivity was obtained with each medium. The SMID and Rambach agars are considerably more specific than the conventional media. Although SMID agar detects all Salmonella serotypes, it is not as specific as Rambach agar, which requires a complementary test (C8 esterase test) to detect all serotypes.
European Journal of Clinical Microbiology 04/1994; 13(3):257-61. DOI:10.1007/BF01974547 · 2.67 Impact Factor
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