Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: September 21, 2003
Publication Date: September 21, 2003
Citation: BEARSON, S.M., BEARSON, B.L. IDENTIFYING SALMONELLA ENTERICA SEROVAR TYPHIMURIUM GENES IMPORTANT FOR SURVIVAL IN THE SWINE STOMACH USING SIGNATURE-TAGGED MUTAGENESIS. GENOMIC SEQUENCE AND ANALYSIS CONFERENCE. 2003. ABSTRACT p. P101. Technical Abstract: Causing an estimated 1.3 million U.S. cases of foodborne disease annually, Salmonella is an important food safety concern. According to the 2000 USDA NAHMS report, 34% of U.S. swine herds are infected with Salmonella. A major exposure route of swine to Salmonella is the oral route; hence, one of the first host defense mechanisms that Salmonella will encounter is the volatile environment of the stomach. To identify Salmonella enterica serovar Typhimurium genes important for survival in the swine stomach, the functional genomics technique Signature-Tagged Mutagenesis was employed. STM is an insertional mutagenesis system with transposons carrying unique DNA sequence tags; therefore, in a complex pool of mutants, each S. typhimurium mutant is identifiable in a negative selection screen. Of the 528 S. typhimurium mutants screened to date in the in vitro swine stomach content assay, 23 mutants display a decrease in survival. A mutation was identified in the pefA gene, a member of the virulence plasmid-encoded fimbriae operon involved in epithelial cell attachment. Although the pH of the swine stomach content assay is 4.02, no difference in acid sensitivity was observed between the pefA mutant and the wild-type strain in the acid tolerance response assay at pH 3; thus, the possibility exists that the pefA mutation renders Salmonella sensitive to another swine stomach component.