title: Cell invasion of poultry-associated Salmonella enterica serovar Enteritidis isolates is associated with pathogenicity, motility and proteins secreted by the type III secretion system.
abstract: Salmonella enterica serovar Enteritidis (S. Enteritidis) is a major cause of food-borne gastroenteritis in humans worldwide. Poultry and poultry products are considered the major vehicles of transmission to humans. Using cell invasiveness as a surrogate marker for pathogenicity, we tested the invasiveness of 53 poultry-associated isolates of S. Enteritidis in a well-differentiated intestinal epithelial cell model (Caco-2). The method allowed classification of the isolates into low (n = 7), medium (n = 18) and high (n = 30) invasiveness categories. Cell invasiveness of the isolates did not correlate with the presence of the virulence-associated gene spvB or the ability of the isolates to form biofilms. Testing of representative isolates with high and low invasiveness in a mouse model revealed that the former were more invasive in vivo and caused more and earlier mortalities, whereas the latter were significantly less invasive in vivo, causing few or no mortalities. Further characterization of representative isolates with low and high invasiveness showed that most of the isolates with low invasiveness had impaired motility and impaired secretion of either flagella-associated proteins (FlgK, FljB and FlgL) or type III secretion system (TTSS)-secreted proteins (SipA and SipD) encoded on Salmonella pathogenicity island-1. In addition, isolates with low invasiveness had impaired ability to invade and/or survive within chicken macrophages. These data suggest that not all isolates of S. Enteritidis recovered from poultry may be equally pathogenic, and that the pathogenicity of S. Enteritidis isolates is associated, in part, with both motility and secretion of TTSS effector proteins.
authors.affiliation: Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA.
authors.forename: Devendra H
authors.initials: DH
authors.lastname: Shah
authors.affiliation: WSU-Zoonoses Unit, Washington State University, Pullman, WA 99164, USA.|Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Zhou
authors.affiliation: Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA.
authors.forename: Tarek
authors.initials: T
authors.lastname: Addwebi
authors.affiliation: Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA.
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Davis
authors.affiliation: Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA.
authors.forename: Lisa
authors.initials: L
authors.lastname: Orfe
authors.affiliation: Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA.
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Call
authors.affiliation: Egg Quality and Safety Research Unit, Agriculture Research Service, United States Department of Agriculture, Athens, GA 30605, USA.
authors.forename: Jean
authors.initials: J
authors.lastname: Guard
authors.affiliation: Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Besser
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms; D018938:Caco-2 Cells; D002645:Chickens; D005260:Female; D005506:Food Contamination; D044404:Genomic Islands; D006801:Humans; D053208:Kaplan-Meier Estimate; D008460:Meat / Q000382:microbiology; D051379:Mice; D008807:Mice, Inbred BALB C; D008954:Models, Biological; D008969:Molecular Sequence Data; D010802:Phylogeny; D011201:Poultry Diseases / Q000382:microbiology*; D021381:Protein Transport; D012480:Salmonella Infections / Q000382:microbiology* / Q000401:mortality; D012481:Salmonella Infections, Animal / Q000382:microbiology* / Q000401:mortality; D012477:Salmonella enteritidis / Q000145:classification / Q000235:genetics / Q000472:pathogenicity* / Q000502:physiology*; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D037521:Virulence Factors