Genomics and Pathogenesis of Salmonella enterica serovars Typhi and Paratyphi A
Kathryn E Holt, Tim T Perkins, Gordon Dougan and Robert A Kingsley
from: Salmonella: From Genome to Function (Edited by: Steffen Porwollik). Caister Academic Press, U.K. (2011)
The genomics era has transformed the way that we can study bacterial pathogens. The availability of two complete and 17 draft genomes of S. Typhi has made it possible to study the phylogenetic structure of this pathogen in unparalleled resolution, monitor gene flux, accumulation of pseudogenes, neutral mutations and loci under selective pressure. We describe the molecular basis of Salmonella Typhi pathogenesis, in particular where genomics has contributed to our understanding in the past decade. Potentially important S. Typhi-specific virulence determinants include the Vi polysaccharide capsule, the type IV pilus, and a unique repertoire of fimbria. These may account for key differences in the disease outcome of this pathogen compared with non-typhoidal serotypes. Genome comparison with the closely related serotype S. Paratyphi A identifies a core set of pseudogenes, some of which emerged independently, that may define important features of genome degradation associated with host restriction and pathogenesis of invasive disease. Geo-phylogenetics of S. Typhi constructed from single nucleotide polymorphism data from high throughput draft genome sequences is now being applied to study molecular epidemiology in the field read more ...