title: Analysis of Salmonella enterica serotype-host specificity in calves: avirulence of S. enterica serotype gallinarum correlates with bacterial dissemination from mesenteric lymph nodes and persistence in vivo.
abstract: Host and bacterial factors that determine whether Salmonella serotypes remain restricted to the gastrointestinal tract or penetrate beyond the mucosa and cause systemic disease remain largely undefined. Here, factors influencing Salmonella host specificity in calves were assessed by characterizing the pathogenesis of different serotypes. Salmonella enterica serotype Dublin was highly virulent intravenously, whereas S. enterica serotype Choleraesuis was moderately virulent. Both serotypes were virulent in calves infected orally. In contrast, S. enterica serotypes Gallinarum and Abortusovis were avirulent by either route. Serotypes Dublin, Gallinarum, and Abortusovis colonized the intestinal tract 24 h after oral inoculation, yet only serotype Dublin was consistently recovered from systemic tissues. Serotypes Dublin and Gallinarum invaded bovine intestines in greater numbers and induced greater enteropathogenic responses than serotypes Choleraesuis and Abortusovis. However, only serotype Dublin was able to persist within the intestinal mucosa, and use of a novel cannulation model demonstrated that serotype Dublin was able to pass through the mesenteric lymph nodes in greater numbers than serotype Gallinarum. Together, these results suggest that initial interactions with the intestinal mucosa do not correlate with host specificity, although persistence within tissues and translocation via efferent lymphatics appear to be crucial for the induction of bovine salmonellosis.
authors.affiliation: Institute for Animal Health, Compton, Newbury, Berkshire, RG20 7NN, United Kingdom.
authors.forename: Susan M
authors.initials: SM
authors.lastname: Paulin
authors.forename: Patricia R
authors.initials: PR
authors.lastname: Watson
authors.forename: Annette R
authors.initials: AR
authors.lastname: Benmore
authors.forename: Mark P
authors.initials: MP
authors.lastname: Stevens
authors.forename: Philip W
authors.initials: PW
authors.lastname: Jones
authors.forename: Bernardo
authors.initials: B
authors.lastname: Villarreal-Ramos
authors.forename: Timothy S
authors.initials: TS
authors.lastname: Wallis
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology*; D007413:Intestinal Mucosa / Q000382:microbiology; D008198:Lymph Nodes / Q000382:microbiology*; D012481:Salmonella Infections, Animal / Q000382:microbiology*; D019779:Salmonella enterica / Q000145:classification* / Q000302:isolation & purification / Q000472:pathogenicity*; D012703:Serotyping; D013045:Species Specificity; D013152:Splanchnic Circulation; D014774:Virulence