title: Poultry body temperature contributes to invasion control through reduced expression of Salmonella pathogenicity island 1 genes in Salmonella enterica serovars Typhimurium and Enteritidis.
abstract: Salmonella enterica serovars Typhimurium (S. Typhimurium) and Enteritidis (S. Enteritidis) are foodborne pathogens, and outbreaks are often associated with poultry products. Chickens are typically asymptomatic when colonized by these serovars; however, the factors contributing to this observation are uncharacterized. Whereas symptomatic mammals have a body temperature between 37°C and 39°C, chickens have a body temperature of 41°C to 42°C. Here, in vivo experiments using chicks demonstrated that numbers of viable S. Typhimurium or S. Enteritidis bacteria within the liver and spleen organ sites were ≥4 orders of magnitude lower than those within the ceca. When similar doses of S. Typhimurium or S. Enteritidis were given to C3H/HeN mice, the ratio of the intestinal concentration to the liver/spleen concentration was 1:1. In the avian host, this suggested poor survival within these tissues or a reduced capacity to traverse the host epithelial layer and reach liver/spleen sites or both. Salmonella pathogenicity island 1 (SPI-1) promotes localization to liver/spleen tissues through invasion of the epithelial cell layer. Following in vitro growth at 42°C, SPI-1 genes sipC, invF, and hilA and the SPI-1 rtsA activator were downregulated compared to expression at 37°C. Overexpression of the hilA activators fur, fliZ, and hilD was capable of inducing hilA-lacZ at 37°C but not at 42°C despite the presence of similar levels of protein at the two temperatures. In contrast, overexpression of either hilC or rtsA was capable of inducing hilA and sipC at 42°C. These data indicate that physiological parameters of the poultry host, such as body temperature, have a role in modulating expression of virulence.
authors.affiliation: Prestage Department of Poultry Science, North Carolina State University, Raleigh, North Carolina, USA bryan_troxell@ncsu.edu.
authors.forename: Bryan
authors.initials: B
authors.lastname: Troxell
authors.affiliation: Prestage Department of Poultry Science, North Carolina State University, Raleigh, North Carolina, USA.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Petri
authors.affiliation: Prestage Department of Poultry Science, North Carolina State University, Raleigh, North Carolina, USA.
authors.forename: Caitlyn
authors.initials: C
authors.lastname: Daron
authors.affiliation: Department of Animal Science, University of Sao Paulo, Piracicaba, SP, Brazil.
authors.forename: Rafaela
authors.initials: R
authors.lastname: Pereira
authors.affiliation: Prestage Department of Poultry Science, North Carolina State University, Raleigh, North Carolina, USA.
authors.forename: Mary
authors.initials: M
authors.lastname: Mendoza
authors.affiliation: Prestage Department of Poultry Science, North Carolina State University, Raleigh, North Carolina, USA.
authors.forename: Hosni M
authors.initials: HM
authors.lastname: Hassan
authors.affiliation: Prestage Department of Poultry Science, North Carolina State University, Raleigh, North Carolina, USA.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Koci
mesh_terms: D000818:Animals; D002432:Cecum / Q000382:microbiology / Q000502:physiology; D002645:Chickens; D044404:Genomic Islands; D008099:Liver / Q000382:microbiology / Q000502:physiology; D011201:Poultry Diseases / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology; D012481:Salmonella Infections, Animal / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology; D012477:Salmonella enteritidis / Q000235:genetics / Q000502:physiology*; D012486:Salmonella typhimurium / Q000235:genetics / Q000502:physiology*; D013154:Spleen / Q000382:microbiology / Q000502:physiology; D013696:Temperature