pathogenesis
Last reviewed 01/2018
The clinical effects of Salmonella inoculation depends upon the organism's virulence factors and host defence factors.
Host factors:
- very young or very old, other illness, immune suppression, gastric hypochlorhydria - infecting dose must usually be greater than 100,000 organism though in the presence of hypochlorhydria, a lower infective dose may cause illness
Virulence factors:
- S. cholerae suis is prone to cause septicaemia
- S. virchow and S. dublin have increased invasive potential
- S. typhimurium may possess specific plasmids increasing virulence
Once infection is established, diarrhoea occurs due to enterotoxin-induced electrolyte transport defects across the intestinal mucosa of the ileum and due to invasive inflammation of the colon and lower ileum.