The putative sigma factor KatF (RpoS) is required for the transcription of the Salmonella typhimurium virulence gene spvB in Escherichia coli

Norel, Françoise

doi:10.1016/0378-1097(92)90039-q

Cited by 43 publications

(55 citation statements)

References 15 publications

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“…This is consistent with the hypothesis that rpoS contributes to the pathogenesis of Salmonella serotype Typhimurium in humans. RpoS controls expression of the virulence plasmid genes, spvRABCD (8,31). These genes do not contribute to the pathogenesis of Salmonella gastroenteritis but appear to be associated with systemic infections in animals and humans (11,28).…”

Section: Discussionmentioning

confidence: 99%

“…RpoS plays a key role in the virulence of Salmonella in mice (5,6,8,24,30,31). Salmonellae are enteric pathogens that cause a wide range of host-and serotype-specific illnesses, including gastroenteritis and enteric fever.…”

mentioning

confidence: 99%

“…In Salmonella serotype Typhimurium, S controls expression of the Salmonella virulence plasmid genes, spvRABCD (8,31), which control the growth rate of Salmonella in deep organs (for a review see reference 12). The spvB gene product is an ADPribosyltransferase that may promote the growth of Salmonella within macrophages (26,33,43).…”

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confidence: 99%

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Characterization of the RpoS Status of Clinical Isolates of Salmonella enterica

Robbe‐Saule

Algorta

Rouilhac

et al. 2003

Appl Environ Microbiol

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The stationary-phase-inducible sigma factor, S (RpoS), is the master regulator of the general stress response in Salmonella and is required for virulence in mice. rpoS mutants can frequently be isolated from highly passaged laboratory strains of Salmonella. We examined the rpoS status of 116 human clinical isolates of Salmonella, including 41 Salmonella enterica serotype Typhi strains isolated from blood, 38 S. enterica serotype Typhimurium strains isolated from blood, and 37 Salmonella serotype Typhimurium strains isolated from feces. We examined the abilities of these strains to produce the S protein, to express RpoS-dependent catalase activity, and to resist to oxidative stress in the stationary phase of growth. We also carried out complementation experiments with a cloned wild-type rpoS gene. Our results showed that 15 of the 41 Salmonella serotype Typhi isolates were defective in RpoS. We sequenced the rpoS allele of 12 strains. This led to identification of small insertions, deletions, and point mutations resulting in premature stop codons or affecting regions 1 and 2 of S , showing that the rpoS mutations are not clonal. Thus, mutant rpoS alleles can be found in freshly isolated clinical strains of Salmonella serotype Typhi, and they may affect virulence properties. Interestingly however, no rpoS mutants were found among the 75 Salmonella serotype Typhimurium isolates. Strains that differed in catalase activity and resistance to hydrogen peroxide were found, but the differences were not linked to the rpoS status. This suggests that Salmonella serotype Typhimurium rpoS mutants are counterselected because rpoS plays a role in the pathogenesis of Salmonella serotype Typhimurium in humans or in the transmission cycle of the disease.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

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Characterization of the RpoS Status of Clinical Isolates of Salmonella enterica

Robbe‐Saule

Algorta

Rouilhac

et al. 2003

Appl Environ Microbiol

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“…The sp genes are expressed during the stationary growth phase and during the intracellular stages of infection [226]. Curing of the SAP or deletion of the sp region abolishes the virulence of these serotypes in animal models [87,[227][228][229].…”

Section: The Virulence Plasmidmentioning

confidence: 99%

Host adapted serotypes of Salmonella enterica

et al. 2000

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Salmonella constitutes a genus of zoonotic bacteria of worldwide economic and health importance. The current view of salmonella taxonomy assigns the members of this genus to two species: S. enterica and S. bongori. S. enterica itself is divided into six subspecies, enterica, salamae, arizonae, diarizonae, indica, and houtenae, also known as subspecies I, II, IIIa, IIIb, IV, and VI, respectively [1]. Members of Salmonella enterica subspecies enterica are mainly associated with warm-blooded vertebrates and are usually transmitted by ingestion of food or water contaminated by infected faeces. The pathogenicity of most of the distinct serotypes remains undefined, and even within the most common serotypes, many questions remain to be answered regarding the interactions between the organism and the infected host.Salmonellosis manifests itself in three major forms: enteritis, septicaemia, and abortion, each of which may be present singly or in combination, depending on both the serotype and the host involved. Although currently over 2300 serovars of Salmonella are recognized, only about 50 serotypes are isolated in any significant numbers as human or animal pathogens [2, 3] and they all belong to subspecies enterica. Of these, most cause acute gastroenteritis characterized by a short incubation period and a severe systemic disease in man or animals, characterized by septicaemia, fever and/or abortion, and such serotypes are often associated with one or few host species [4–6].It is the intention of this review to present a summary of current knowledge of these host-adapted serotypes of S. enterica. The taxonomic relationships between the serotypes will be discussed together with a comparison of the pathology and pathogenesis of the disease that they cause in their natural host(s). Since much of our knowledge on salmonellosis is based on the results of work on Typhimurium, this serotype will often be used as the baseline in discussion. It is hoped that an appreciation of the differences that exist in the way these serotypes interact with the host will lead to a greater understanding of the complex host–parasite relationship that characterizes salmonella infections.

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“…In Salmonella, the rpoS gene encodes an alternative sigma factor (σ s /RpoS) that is the master regulator in the general stress response and is required for survival under extreme conditions, including osmotic and oxidative stress, transition to stationary phase, acid shock, [43,44] and for virulence of S. Typhimurium [45,46,47,48,49]. RpoS controls expression of the S. Typhimurium virulence plasmid genes, spvRABCD [46,47].…”

Section: Effect Of Rpos On VI Synthesismentioning

confidence: 99%

Regulation of Vi Capsular Polysaccharide Synthesis in Salmonella enterica Serotype Typhi

Santander

Roland

Curtiss

2008

J Infect Dev Ctries

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The synthesis of Vi polysaccharide, a major virulence determinant in Salmonella enterica serotype Typhi (S. Typhi), is under the control of two regulatory systems, ompR-envZ and rscB-rscC, which respond to changes in osmolarity. Some S. Typhi isolates exhibit over-expression of Vi polysaccharide, which masks clinical detection of LPS O-antigen. This variation in Vi polysaccharide and O-antigen display (VW variation) has been observed since the initial studies of S. Typhi. We have reported that the status of the rpoS gene is responsible for this phenomenon. We review the regulatory network of the Vi polysaccharide, linking osmolarity and RpoS expression. Also, we discuss how this may impact live attenuated Salmonella vaccine development.

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The putative sigma factor KatF (RpoS) is required for the transcription of the Salmonella typhimurium virulence gene spvB in Escherichia coli

Cited by 43 publications

References 15 publications

Characterization of the RpoS Status of Clinical Isolates of Salmonella enterica

Characterization of the RpoS Status of Clinical Isolates of Salmonella enterica

Host adapted serotypes of Salmonella enterica

Regulation of Vi Capsular Polysaccharide Synthesis in Salmonella enterica Serotype Typhi

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