title: Invasiveness of Salmonella serotypes Typhimurium and Enteritidis of human gastro-enteritic origin for rabbit ileum: role of LPS, plasmids and host factors.
abstract: An organ culture system involving explants of distal rabbit ileum was used to study the roles of lipopolysaccharide (LPS) and plasmids in primary invasiveness for enterocytes in situ of strains of Salmonella serotypes Typhimurium and Enteritidis. Long-chain LPS per se does not confer invasiveness on Typhimurium, as known avirulent, hypo-invasive strains express smooth LPS. However, the invasiveness of a naturally occurring rough isogenic derivative of Salmonella serotype Enteritidis PT 4 was about half that of its wild-type parent. Therefore, smooth LPS appears to play a secondary role in maximising invasiveness. No evidence was found to correlate primary invasiveness for gut of 18 strains of Typhimurium with plasmid profiles in general or with the 60-MDa serovar-specific virulence plasmid in particular. Evidence is presented that strongly suggests a seasonal variability in susceptibility of rabbit gut to invasion by Typhimurium. Although no explanation is given for this summer insusceptibility, the data indicate the importance of the physiological status of the host in relation to susceptibility to invasion by Salmonella.
authors.forename: Gillian D
authors.initials: GD
authors.lastname: Martin
authors.affiliation: Microbial Molecular Genetics and Cell Biology Group, School of Biological Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT and *Laboratory of Enteric Pathogens, Public Health Laboratory Service, 61 Colindale Avenue, London NW9 5HT.
authors.forename: Henrik
authors.initials: H
authors.lastname: Chart
authors.affiliation: Microbial Molecular Genetics and Cell Biology Group, School of Biological Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT and *Laboratory of Enteric Pathogens, Public Health Laboratory Service, 61 Colindale Avenue, London NW9 5HT.
authors.forename: E John
authors.initials: EJ
authors.lastname: Threlfall
authors.forename: Eirwen
authors.initials: E
authors.lastname: Morgan
authors.forename: Julia M
authors.initials: JM
authors.lastname: Lodge
authors.forename: Nigel L
authors.initials: NL
authors.lastname: Brown
authors.forename: John
authors.initials: J
authors.lastname: Stephen
mesh_terms: D000818:Animals; D005759:Gastroenteritis / Q000382:microbiology*; D006801:Humans; D007082:Ileum / Q000382:microbiology*; D008070:Lipopolysaccharides / Q000032:analysis; D010957:Plasmids / Q000502:physiology; D011817:Rabbits; D012480:Salmonella Infections / Q000382:microbiology*; D012477:Salmonella enteritidis / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D012486:Salmonella typhimurium / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D012621:Seasons; D014774:Virulence / Q000235:genetics
chemical_list: D008070:Lipopolysaccharides