The shdA gene is restricted to serotypes of Salmonella enterica subspecies I and contributes to efficient and prolonged fecal shedding

Robert A. Kingsley, Karin Van Amsterdam, Naomi Kramer, Andreas J Baumler

Research output: Contribution to journalArticle

87 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)2720-2727
Number of pages8
JournalInfection and Immunity
Issue number5
StatePublished - May 2000
Externally publishedYes


ASJC Scopus subject areas

  • Immunology

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