title: Identification of host-specific colonization factors of Salmonella enterica serovar Typhimurium.
abstract: The severity of infections caused by Salmonella enterica serovar Typhimurium varies depending on the host species. Numerous virulence genes have been identified in S. Typhimurium, largely from studies in mice, but their roles in infections of other species remain unclear. In the most comprehensive survey of its kind, through the use of signature-tagged mutagenesis of S. Typhimurium we have identified mutants that were unable to colonize calf intestines, mutants unable to colonize chick intestines and mutants unable to colonize both species. The type three secretion systems encoded on Salmonella pathogenicity islands (SPIs) 1 and 2 were required for efficient colonization of cattle. However, disruption of these secretion systems only caused a minor defect in S. Typhimurium colonization of chicks. Transposon insertions in SPI-4 compromised S. Typhimurium colonization of cattle, but not chicks. This is the first data confirming a role for SPI-4 in pathogenesis. We have also been able to ascribe a role in colonization for cell surface polysaccharides, cell envelope proteins, and many 'housekeeping' genes and genes of unknown function. We conclude that S. Typhimurium uses different strategies to colonize calves and chicks. This has major implications for vaccine design.
authors.affiliation: Division of Microbiology, Institute for Animal Health, Compton, Nr Newbury, RG20 7NN, UK.
authors.forename: Eirwen
authors.initials: E
authors.lastname: Morgan
authors.forename: June D
authors.initials: JD
authors.lastname: Campbell
authors.forename: Sonya C
authors.initials: SC
authors.lastname: Rowe
authors.forename: Jennie
authors.initials: J
authors.lastname: Bispham
authors.forename: Mark P
authors.initials: MP
authors.lastname: Stevens
authors.forename: Alison J
authors.initials: AJ
authors.lastname: Bowen
authors.forename: Paul A
authors.initials: PA
authors.lastname: Barrow
authors.forename: Duncan J
authors.initials: DJ
authors.lastname: Maskell
authors.forename: Timothy S
authors.initials: TS
authors.lastname: Wallis
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002417:Cattle; D002642:Chick Embryo; D004251:DNA Transposable Elements; D005243:Feces / Q000382:microbiology; D005260:Female; D044404:Genomic Islands; D007422:Intestines / Q000382:microbiology; D016676:Macrophages, Alveolar / Q000378:metabolism; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D016296:Mutagenesis; D012480:Salmonella Infections; D012486:Salmonella typhimurium / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity*; D013552:Swine; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D037521:Virulence Factors