Analysis of the contribution of Salmonella pathogenicity islands 1 and 2 to enteric disease progression using a novel bovine ileal loop model and a murine model of infectious enterocolitis.
We have developed a novel ileal loop model for use in calves to analyze the contribution of Salmonella enterica serovar Typhimurium type III secretion systems to disease processes in vivo. Our model involves constructing ileal loops with end-to-end anastamoses to restore the patency of the small intestine, thereby allowing experimental animals to convalesce following surgery for the desired number of days. This model overcomes the time constraint imposed by ligated ileal loop models that have precluded investigation of Salmonella virulence factors during later stages of the infection process. Here, we have used this model to examine the enteric disease process at 24 h and 5 days following infection with wild-type Salmonella and mutants lacking the virulence-associated Salmonella pathogenicity island 1 (SPI-1) or SPI-2 type III secretion systems. We show that SPI-2 mutants are dramatically attenuated at 5 days following infection and report a new phenotype for SPI-1 mutants, which induce intestinal pathology in calves similar to wild-type Salmonella in the 5-day ileal loop model. Both of these temporal phenotypes for SPI-1 and SPI-2 mutants were corroborated in a second animal model of enteric disease using streptomycin-pretreated mice. These data delineate novel phenotypes for SPI-1 and SPI-2 mutants in the intestinal phase of bovine and murine salmonellosis and provide working models to further investigate the effector contribution to these pathologies.
Coombes
Brian K
BK
Michael Smith Laboratories, 301-2185 East Mall, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
Coburn
Bryan A
BA
Potter
Andrew A
AA
Gomis
Susantha
S
Mirakhur
Kuldip
K
Li
Yuling
Y
Finlay
B Brett
BB
D000818:Animals; D002417:Cattle; D002432:Cecum / Q000473:pathology; D004195:Disease Models, Animal; D018450:Disease Progression; D004760:Enterocolitis / Q000382:microbiology / Q000503:physiopathology*; D044404:Genomic Islands / Q000235:genetics / Q000502:physiology*; D007082:Ileum / Q000382:microbiology / Q000503:physiopathology*; D007249:Inflammation / Q000382:microbiology / Q000503:physiopathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009154:Mutation; D010641:Phenotype; D012481:Salmonella Infections, Animal / Q000382:microbiology / Q000503:physiopathology*; D012486:Salmonella typhimurium / Q000235:genetics* / Q000472:pathogenicity*; D013307:Streptomycin; D014774:Virulence
D013307:Streptomycin