title: The shdA gene is restricted to serotypes of Salmonella enterica subspecies I and contributes to efficient and prolonged fecal shedding.
abstract: Little is known about factors which enable Salmonella serotypes to circulate within populations of livestock and domestic fowl. We have identified a DNA region which is present in Salmonella serotypes commonly isolated from livestock and domestic fowl (S. enterica subspecies I) but absent from reptile-associated Salmonella serotypes (S. bongori and S. enterica subspecies II to VII). This DNA region was cloned from Salmonella serotype Typhimurium and sequence analysis revealed the presence of a 6,105-bp open reading frame, designated shdA, whose product's deduced amino acid sequence displayed homology to that of AIDA-I from diarrheagenic Escherichia coli, MisL of serotype Typhimurium, and IcsA of Shigella flexneri. The shdA gene was located adjacent to xseA at 52 min, in a 30-kb DNA region which is not present in Escherichia coli K-12. A serotype Typhimurium shdA mutant was shed with the feces in reduced numbers and for a shorter period of time compared to its isogenic parent. A possible role for the shdA gene during the expansion in host range of S. enterica subspecies I to include warm-blooded vertebrates is discussed.
authors.affiliation: Department of Medical Microbiology and Immunology, College of Medicine, Texas A&M University Health Science Center, College Station, Texas 77843-1114, USA.
authors.forename: R A
authors.initials: RA
authors.lastname: Kingsley
authors.forename: K
authors.initials: K
authors.lastname: van Amsterdam
authors.forename: N
authors.initials: N
authors.lastname: Kramer
authors.forename: A J
authors.initials: AJ
authors.lastname: Bäumler
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D001483:Base Sequence; D004269:DNA, Bacterial; D005090:Exodeoxyribonucleases / Q000235:genetics; D005243:Feces / Q000382:microbiology; D005260:Female; D005798:Genes, Bacterial; D006643:Histidine-tRNA Ligase / Q000235:genetics; D006801:Humans; D007421:Intestine, Small / Q000382:microbiology; D051379:Mice; D008807:Mice, Inbred BALB C; D008954:Models, Biological; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009924:Organ Culture Techniques; D010581:Peyer's Patches / Q000382:microbiology; D012480:Salmonella Infections / Q000382:microbiology*; D019779:Salmonella enterica / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D012703:Serotyping
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D004269:DNA, Bacterial; C409034:ShdA protein, Salmonella enterica; C075518:invA protein, Bacteria; D005090:Exodeoxyribonucleases; C026870:exodeoxyribonuclease VII; D006643:Histidine-tRNA Ligase