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Composition, Acquisition, and Distribution of the Vi Exopolysaccharide-Encoding Salmonella enterica Pathogenicity Island SPI-7.
- Source :
-
Journal of Bacteriology . Sep2003, Vol. 185 Issue 17, p5055-5065. 11p. 8 Diagrams, 3 Charts. - Publication Year :
- 2003
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Abstract
- Vi capsular polysaccharide production is encoded by the viaB locus, which has a limited distribution in Salmonella enterica serovars. In S. enterica serovar Typhi, viaB is encoded on a 134-kb pathogenicity island known as SPI-7 that is located between partially duplicated tRNA[sup pheU] sites. Functional and bioinformatic analysis suggests that SPI-7 has a mosaic structure and may have evolved as a consequence of several independent insertion events. Analysis of viaB-associated DNA in Vi-positive S. enterica serovar Paratyphi C and S. enterica serovar Dublin isolates revealed the presence of similar SPI-7 islands. In S. enterica serovars Paratyphi C and Dublin, the SopE bacteriophage and a 15-kb fragment adjacent to the intact tRNA[sup pheU] site were absent. In S. enterica serovar Paratyphi C only, a region encoding a type IV pilus involved in the adherence or S. enterica serovar Typhi to host cells was missing. The remainder of the SPI-7 islands investigated exhibited over 99% DNA sequence identity in the three serovars. Of 30 other Salmonella serovars examined, 24 contained no insertions at the equivalent tRNA[sup pheU] site, 2 had a 3.7-kb insertion, and 4 showed sequence variation at the tRNA[sup pheU]-phoN junction, which was not analyzed further. Sequence analysis of the SPI-7 region from S. enterica serovar Typhi strain CT18 revealed significant synteny with clusters of genes from a variety of saprophytic bacteria and phytobacteria, including Pseudomonas aeruginosa and Xanthomonas axonopodis pv. citri. This analysis suggested that SPI-7 may be a mobile element, such as a conjugative transposon or an integrated plasmid remnant. [ABSTRACT FROM AUTHOR]
- Subjects :
- *SALMONELLA
*MICROBIAL exopolysaccharides
*BACTERIOLOGY
Subjects
Details
- Language :
- English
- ISSN :
- 00219193
- Volume :
- 185
- Issue :
- 17
- Database :
- Academic Search Index
- Journal :
- Journal of Bacteriology
- Publication Type :
- Academic Journal
- Accession number :
- 10893598
- Full Text :
- https://doi.org/10.1128/JB.185.17.5055-5065.2003