title: Molecular and phenotypic analysis of the CS54 island of Salmonella enterica serotype typhimurium: identification of intestinal colonization and persistence determinants.
abstract: The shdA gene is carried on a 25-kb genetic island at centisome 54 (CS54 island) of the Salmonella enterica serotype Typhimurium chromosome. In addition to shdA, the CS54 island of Salmonella serotype Typhimurium strain LT2 contains four open reading frames designated ratA, ratB, sivI, and sivH. DNA hybridization analysis revealed that the CS54 island is comprised of two regions with distinct phylogenetic distribution within the genus Salmonella. Homologues of shdA and ratB were detected only in serotypes of Salmonella enterica subsp. I. In contrast, sequences hybridizing with ratA, sivI, and sivH were present in S. enterica subsp. II and S. bongori in addition to S. enterica subsp. I. Deletion of the ratA and sivI genes did not alter the ability of Salmonella serotype Typhimurium to colonize the organs of mice. Insertional inactivation of the sivH gene resulted in defective colonization of the Peyer's patches of the terminal ileum but normal colonization of the cecum, mesenteric lymph nodes, and spleen. Deletion of the shdA gene resulted in decreased colonization of the cecum and Peyer's patches of the terminal ileum and colonization to a lesser degree in the mesenteric lymph nodes and spleen 5 days post-oral inoculation of mice. A strain containing a deletion in the ratB gene exhibited a defect for the colonization of the cecum but not of the Peyer's patches, mesenteric lymph nodes, and spleen. The shdA and ratB deletion strains exhibited a shedding defect in mice, whereas the sivH deletion strain was shed at numbers similar to the wild type. These data suggest that colonization of the murine cecum is required for efficient fecal shedding in mice.
authors.affiliation: Department of Medical Microbiology and Immunology, College of Medicine, Texas A&M University System Health Science Center, College Station 77843-1114, USA.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Kingsley
authors.forename: Andrea D
authors.initials: AD
authors.lastname: Humphries
authors.forename: Eric H
authors.initials: EH
authors.lastname: Weening
authors.forename: Marcel R
authors.initials: MR
authors.lastname: De Zoete
authors.forename: Sebastian
authors.initials: S
authors.lastname: Winter
authors.forename: Anastasia
authors.initials: A
authors.lastname: Papaconstantinopoulou
authors.forename: Gordon
authors.initials: G
authors.lastname: Dougan
authors.forename: Andreas J
authors.initials: AJ
authors.lastname: Bäumler
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D002432:Cecum / Q000382:microbiology*; D005243:Feces / Q000382:microbiology; D017353:Gene Deletion; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008808:Mice, Inbred CBA; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010581:Peyer's Patches / Q000382:microbiology; D010641:Phenotype; D012481:Salmonella Infections, Animal / Q000382:microbiology*; D012486:Salmonella typhimurium / Q000145:classification / Q000235:genetics / Q000254:growth & development* / Q000472:pathogenicity*; D014774:Virulence
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; C409034:ShdA protein, Salmonella enterica