Progress in Vaccines Against Typhoid Fever

Levine, Myron M.; Ferreccio, Catterine; Black, Robert E.; Tacket, Carol O.; Germanier, R

doi:10.1093/clinids/11.supplement_3.s552

Cited by 169 publications

(98 citation statements)

References 47 publications

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“…In addition, using reverse transcriptase PCR analysis, we have found that this polycistronic message extends downstream of prgH to include a total of 10 genes. To more fully characterize this invasion operon, we demonstrate that the prgH, prgI, prgJ, prgK, orgA, and orgB genes are each required for invasion and secretion, while orgC is not essential for the invasive phenotype.Salmonella infections are an important health problem in both the developing and developed world (9,32,34). Pathogenic Salmonella species cause infections that range in severity from self-limiting gastroenteritis to life-threatening systemic dissemination (45).…”

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confidence: 99%

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Transcriptional Organization and Function of Invasion Genes within Salmonella enterica Serovar Typhimurium Pathogenicity Island 1, Including the prgH , prgI , prgJ , prgK , orgA , orgB , and orgC Genes

2000

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Salmonella enterica serovar Typhimurium initiates infection of a host by inducing its own uptake into specialized M cells which reside within the epithelium overlaying Peyer's patches. Entry of Salmonella into intestinal epithelial cells is dependent upon invasion genes that are clustered together in Salmonella pathogenicity island 1 (SPI-1). Upon contact between serovar Typhimurium and epithelial cells targeted for bacterial internalization, bacterial proteins are injected into the host cell through a type III secretion system that leads to internalization of the bacteria. Previous work has established that the prgH, -I, -J, and -K and orgA genes reside in SPI-1, and the products of these genes are predicted to be components of the invasion secretion apparatus. We report that an error in the published orgA DNA sequence has been identified so that this region encodes two small genes rather than a single large open reading frame. These genes have been designated orgA and orgB. Additionally, an opening reading frame downstream of orgB, which we have designated orgC, has been identified and partially characterized. Previously published work has indicated that the prgH, -I, -J, and -K genes are transcribed from a promoter distinct from that used by the gene immediately downstream, orgA. Here, we present experiments indicating that orgA expression is driven by the prgH promoter. In addition, using reverse transcriptase PCR analysis, we have found that this polycistronic message extends downstream of prgH to include a total of 10 genes. To more fully characterize this invasion operon, we demonstrate that the prgH, prgI, prgJ, prgK, orgA, and orgB genes are each required for invasion and secretion, while orgC is not essential for the invasive phenotype.Salmonella infections are an important health problem in both the developing and developed world (9,32,34). Pathogenic Salmonella species cause infections that range in severity from self-limiting gastroenteritis to life-threatening systemic dissemination (45). After entry into a host, the bacteria establish infection by attaching to and invading specialized M cells associated with Peyer's patches in the small intestine (5,23,26). Following M-cell invasion and destruction, host-restricted Salmonella species cause localized destruction of the intestinal epithelium (gastroenteritis). In contrast, passage of hostadapted Salmonella species through M cells allows rapid dissemination to the mesenteric lymph nodes and then to the liver and spleen, where unchecked growth causes death (25).A critical determinant in the development of Salmonella disease is the ability of the bacteria to invade cells. Salmonella enterica serovar Typhimurium mutants that are unable to invade tissue culture cells are defective in their ability to invade and destroy M cells (26,43). This defect severely limits the ability of the bacteria to initiate infection and reduces their virulence in mice (14,24,43). Genes required for Salmonella internalization into mammalian cells have been identified (4, 7, ...

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mentioning

confidence: 99%

“…Salmonella infections are an important health problem in both the developing and developed world (9,32,34). Pathogenic Salmonella species cause infections that range in severity from self-limiting gastroenteritis to life-threatening systemic dissemination (45).…”

mentioning

confidence: 99%

Transcriptional Organization and Function of Invasion Genes within Salmonella enterica Serovar Typhimurium Pathogenicity Island 1, Including the prgH , prgI , prgJ , prgK , orgA , orgB , and orgC Genes

2000

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“…The efficacy of Ty21a was assessed in a large number of clinical trials (Table 2), with over 500,000 vaccinated adults and children. Excellent tolerability and an overall protective efficacy of 67-80% (applying 3 doses of enteric-coated capsules or a liquid formulation) were demonstrated for up to seven years [38,44]. The field studies conducted in Santiago (Chile) confirmed the efficacy and tolerability of Ty21a, and provided evidence of indirect protection (herd immunity) [38].…”

Section: S Typhi Ty21amentioning

confidence: 99%

“…Excellent tolerability and an overall protective efficacy of 67-80% (applying 3 doses of enteric-coated capsules or a liquid formulation) were demonstrated for up to seven years [38,44]. The field studies conducted in Santiago (Chile) confirmed the efficacy and tolerability of Ty21a, and provided evidence of indirect protection (herd immunity) [38]. The incidence of typhoid fever fell in the placebo control group in the first field trial during the years in which Ty21a field trials were performed in other parts of Santiago and started to rise again when vaccination with Ty21a was not carried out [45,46].…”

Section: S Typhi Ty21amentioning

confidence: 99%

“…The Ty21a strain is the active constituent of Vivotif ® (Berna Biotech Ltd, Switzerland), currently the only licensed live oral vaccine against typhoid fever [38]. During the production process of the S. Typhi Ty21a vaccine, bacteria are grown in large-scale fermenters under controlled conditions in medium containing a digest of yeast extract, an acid digest of casein, dextrose and galactose.…”

Section: S Typhi Ty21amentioning

confidence: 99%

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Vaccines against typhoid fever

Guzmán

Borsutzky

Griot-Wenk³

et al. 2006

Vaccine

143

106

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A New Typhoid Vaccine Composed of the Vi Capsular Polysaccharide

Plotkin

Cam²

1995

Arch Intern Med

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Typhoid is still prevalent in many parts of the world. We reviewed all published and unpublished studies of a newly licensed vaccine composed of the Vi capsular polysaccharide of Salmonella typhi, the causative agent of the disease, which had been licensed previously outside the United States. These included observational studies and double-blind randomized studies done in the United States, Europe, and the developing world in which children and adults unexposed to typhoid or those living in endemic areas were enrolled. A single dose of 25 micrograms of the purified polysaccharide was given by intramuscular injection. The vaccine was well tolerated, inducing only minor reactions in fewer than 10% of subjects. An antibody response occurred in about 90% of subjects and lasted about 3 years. Seroconversion was shown in children as young as 2 years. Protective efficacy was evaluated in two studies conducted in areas in which typhoid is endemic; the efficacy was 55% and 75%, respectively, in adults and in children older than 5 years. The Vi vaccine compares favorably with other typhoid vaccines in regard to safety, patient compliance, immunogenicity, and efficacy. Vi polysaccharide is a well-standardized antigen that is effective in a single parenteral dose, is safer than whole-cell vaccine, and may be used in children 2 years of age or older.

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Progress in Vaccines Against Typhoid Fever

Cited by 169 publications

References 47 publications

Transcriptional Organization and Function of Invasion Genes within Salmonella enterica Serovar Typhimurium Pathogenicity Island 1, Including the prgH , prgI , prgJ , prgK , orgA , orgB , and orgC Genes

Transcriptional Organization and Function of Invasion Genes within Salmonella enterica Serovar Typhimurium Pathogenicity Island 1, Including the prgH , prgI , prgJ , prgK , orgA , orgB , and orgC Genes

Vaccines against typhoid fever

A New Typhoid Vaccine Composed of the Vi Capsular Polysaccharide

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