title: rpoS-Regulated core genes involved in the competitive fitness of Salmonella enterica Serovar Kentucky in the intestines of chickens.
abstract: Salmonella enterica serovar Kentucky has become the most frequently isolated serovar from poultry in the United States over the past decade. Despite its prevalence in poultry, it causes few human illnesses in the United States. The dominance of S. Kentucky in poultry does not appear to be due to single introduction of a clonal strain, and its reduced virulence appears to correlate with the absence of virulence genes grvA, sseI, sopE, and sodC1. S. Kentucky's prevalence in poultry is possibly attributable to its metabolic adaptation to the chicken cecum. While there were no difference in the growth rate of S. Kentucky and S. Typhimurium grown microaerophilically in cecal contents, S. Kentucky persisted longer when chickens were coinfected with S. Typhimurium. The in vivo advantage that S. Kentucky has over S. Typhimurium appears to be due to differential regulation of core Salmonella genes via the stationary-phase sigma factor rpoS. Microarray analysis of Salmonella grown in cecal contents in vitro identified several metabolic genes and motility and adherence genes that are differentially activated in S. Kentucky. The contributions of four of these operons (mgl, prp, nar, and csg) to Salmonella colonization in chickens were assessed. Deletion of mgl and csg reduced S. Kentucky persistence in competition studies in chickens infected with wild-type or mutant strains. Subtle mutations affecting differential regulation of core Salmonella genes appear to be important in Salmonella's adaptation to its animal host and especially for S. Kentucky's emergence as the dominant serovar in poultry.
authors.affiliation: Poultry Diagnostic and Research Center, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA.
authors.forename: Ying
authors.initials: Y
authors.lastname: Cheng
authors.affiliation: Poultry Diagnostic and Research Center, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA.
authors.forename: Adriana Ayres
authors.initials: AA
authors.lastname: Pedroso
authors.affiliation: Department of Microbiology and Molecular Genetics, University of California, Irvine, Irvine, California, USA.
authors.forename: Steffen
authors.initials: S
authors.lastname: Porwollik
authors.affiliation: Department of Microbiology and Molecular Genetics, University of California, Irvine, Irvine, California, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: McClelland
authors.affiliation: Poultry Diagnostic and Research Center, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA Center for Food Safety, College of Agriculture and Environmental Sciences, University of Georgia, Griffin, Georgia, USA.
authors.forename: Margie D
authors.initials: MD
authors.lastname: Lee
authors.affiliation: Poultry Diagnostic and Research Center, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA.
authors.forename: Tiffany
authors.initials: T
authors.lastname: Kwan
authors.affiliation: Poultry Diagnostic and Research Center, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA.
authors.forename: Katherine
authors.initials: K
authors.lastname: Zamperini
authors.affiliation: Poultry Diagnostic and Research Center, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of Georgia, Athens, Georgia, USA.
authors.forename: Vivek
authors.initials: V
authors.lastname: Soni
authors.affiliation: Poultry Diagnostic and Research Center, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA.
authors.forename: Holly S
authors.initials: HS
authors.lastname: Sellers
authors.affiliation: Department of Poultry Science, College of Agriculture and Environmental Sciences, University of Georgia, Athens, Georgia, USA.
authors.forename: Scott M
authors.initials: SM
authors.lastname: Russell
authors.affiliation: Poultry Diagnostic and Research Center, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA Center for Food Safety, College of Agriculture and Environmental Sciences, University of Georgia, Griffin, Georgia, USA jmaurer@uga.edu.
authors.forename: John J
authors.initials: JJ
authors.lastname: Maurer
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism*; D002645:Chickens / Q000382:microbiology*; D017353:Gene Deletion; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D007422:Intestines / Q000382:microbiology*; D009876:Operon; D018085:Regulon; D012481:Salmonella Infections, Animal / Q000382:microbiology*; D019779:Salmonella enterica / Q000145:classification / Q000235:genetics / Q000502:physiology*; D065288:Serogroup; D012808:Sigma Factor / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D012808:Sigma Factor; C069567:sigma factor KatF protein, Bacteria