Attenuated typhoid vaccine Salmonella typhi Ty21a: fingerprinting and quality control

McKenna, A. J.; Bygraves, Jane A.; Maiden, Martin C. J.; Feavers, Ian M.

doi:10.1099/13500872-141-8-1993

Cited by 15 publications

(6 citation statements)

References 37 publications

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“…Thus, the three reference strains yielded different band profiles with this primer. This observation agrees with those of McKenna et al (1995) on the differentiation of Ty21a vaccine strain from the rest of Salmonella Typhi isolates using a single arbitrary primer, and those reported by Gürakan et al (2008) on the use of a single RAPD primer as a serotype-specific marker for Salmonella Typhimurium.…”

Section: Resultssupporting

confidence: 93%

Typing of Salmonella Typhi strains isolated from Egypt by RAPD PCR

Rezk¹,

Mansour

Ghoneim

et al. 2011

3 Biotech

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PCR-based fingerprinting using random amplified polymorphic DNA (RAPD) has been used widely for genome identification. In this study, 13 Salmonella Typhi strains were isolated from typhoid patients from Aswan, Cairo, Fayoum, and Monofya Governorates of Egypt. The isolates, along with three reference strains, i.e., O901, H901, and Ty2 were subjected to whole genome typing by RAPD PCR. Three RAPD-PCR 10-mer primers generated a total of 85 RAPD bands (81 polymorphic bands), 12 distinct PCR profiles, and proved to be useful for discriminating the isolates and strains studied. Interestingly, the B1 and C1 PCR profile were found only in Cairo and Monofya, respectively; and some PCR types appeared only in certain Governorates of Egypt. By combining the profiles obtained with the primer trio used in this study, an excellent discrimination index (D) of 0.942 was reached. Pairwise comparisons of Jaccard’s similarity coefficients calculated among the 12 PCR types identified three major clusters; i.e., O901 branch and Ty2 and H901 sub-branches. Principal component analysis adequately resolved each of these three major clusters. Three principal components accounted for about 72% of the variation, with the first two components accounting for about 62% of the total variance among the genotypes studied. Biclustering improved the display of groups of RAPD amplicons (markers) that cluster similarly across the genomes and could delineate features pertaining to genome structure. In conclusion, RAPD PCR provided a fast method with high potentials in surveillance and epidemiological investigations of Salmonella Typhi infections.

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Section: Resultssupporting

confidence: 93%

Typing of Salmonella Typhi strains isolated from Egypt by RAPD PCR

Rezk¹,

Mansour

Ghoneim

et al. 2011

3 Biotech

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“…Typhi Ty21a are not fully de¢ned. In addition, a theoretical problem associated with Ty21a is reversion to virulence, although no revertants have been isolated to date [13].…”

Section: Current Typhoid Vaccinesmentioning

confidence: 99%

vaccines for use in humans: present and future perspectives

Garmory¹,

Brown²,

Titball³

2002

FEMS Microbiology Reviews

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In recent years there has been significant progress in the development of attenuated Salmonella enterica serovar Typhi strains as candidate typhoid fever vaccines. In clinical trials these vaccines have been shown to be well tolerated and immunogenic. For example, the attenuated S. enterica var. Typhi strains CVD 908-htrA (aroC aroD htrA), Ty800 (phoP phoQ) and chi4073 (cya crp cdt) are all promising candidate typhoid vaccines. In addition, clinical trials have demonstrated that S. enterica var. Typhi vaccines expressing heterologous antigens, such as the tetanus toxin fragment C, can induce immunity to the expressed antigens in human volunteers. In many cases, the problems associated with expression of antigens in Salmonella have been successfully addressed and the future of Salmonella vaccine development is very promising.

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“…With the advent of vaccines developed genetically, quality control tests based on genetic analyses are necessary. In order to develop novel quality control tests that enhance and extend existing procedures, McKenna et al (1995) characterized the attenuated vaccine strain Salm. typhi Ty21a and its parent Ty2 by a PFGE test and a direct nucleotide sequence analysis.…”

Section: Discussionmentioning

confidence: 99%

“…Although further tests © 1998 The Society for Applied Microbiology, Journal of Applied Microbiology 85, 693-702 are needed to verify the identity of the 350 bp band which distinguished the Ty21a isolate from the rest of the Salm. typhi strains, this simple test may provide a rapid, PCR-based alternative in addition to the molecular genetic test provided by McKenna et al (1995).…”

Section: Discussionmentioning

confidence: 99%

Application of Random Amplified Polymorphic DNA analysis to differentiate strains ofSalmonella typhiand otherSalmonellaspecies

Shangkuan

Lin

1998

Journal of Applied Microbiology

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A Random Amplified Polymorphic DNA (RAPD) fingerprinting method was developed to differentiate isolates of Salmonella serotype typhi (S. typhi) and other Salmonella isolates. A panel of five primers was used to examine 63 isolates of Salm. typhi, including 56 strains isolated in Taiwan and seven strains obtained abroad. Twenty‐one RAPD types were revealed using the RAPD fingerprinting method. An RAPD with primer 6032 yielded a polymorphism in a 350 bp fragment that differentiated the attenuated vaccine strain Salm. typhi Ty21a from the rest of the Salm. typhi strains. Strains of Salm. typhi were divided into five types with primer D14307. Primer D14307 also proved capable of discrimination among 65 other Salmonella isolates representing 42 different serotypes. The bacterial DNA used in this RAPD protocol was obtained using a commercially available DNA extraction kit (GeneReleaser). The DNA of various strains of Salmonella from this simple extraction procedure could be discriminated within a few hours using the RAPD technique.

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Attenuated typhoid vaccine Salmonella typhi Ty21a: fingerprinting and quality control

Cited by 15 publications

References 37 publications

Typing of Salmonella Typhi strains isolated from Egypt by RAPD PCR

Typing of Salmonella Typhi strains isolated from Egypt by RAPD PCR

vaccines for use in humans: present and future perspectives

Application of Random Amplified Polymorphic DNA analysis to differentiate strains ofSalmonella typhiand otherSalmonellaspecies

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