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Pathogenesis of Diarrhea

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Submitted By taraaraneta20
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A. Pathogenesis of Diarrhea

1. Virulence Factors
a. Vibrio cholera 01 and some V. cholera non-01 produce enterotoxins also known as cholera toxins. Escherichia coli also produce Enterotoxins such as heat labile toxin and heat stable toxins. Enterotoxins such as these, act on the intestinal mucosa and cause abnormal net fluid secretion. Moreover, Clostridium perfringes, Bacillus cereus, and some strains of Salmonella typhimurium deem to have similar enterotoxins. Enterotoxin activity has been found in some strains of other bacteria, but their role in producing illness is unclear.
b. CFI and CFII are examples of colonization factors which have been established to be present in many enterogenic E.coli strains that aids them in the colonization of the small intestine.
c. Various enteropathogenic E.coli strains established Adhesive factors. These, perhaps are required for producing illness.
d. Cytotoxins like those produced by strains of Shigella and invasive and non-invasive E.coli may be responsible in at least a fragment for dysentery caused by shigella dysenteriae and probably other shigella and enteroinvasive E.coli and for haemorrhagic colitis and haemolytic uremic syndrome caused by E.coli 0157:H7. Many other enteric organisms have been found to produce cytotoxins but their relevance to disease is unknown.
e. Causes of vomiting are believed to be cause by Neurotoxins present in Staphylococcus aureus and Bacilus cereus.
f. A factor necessary for celluar invasion is the presence of lipopolysaccharide in the cell wall as found in Shigella species. Organisms deprived of this factor are incapable of invading cells in tissue culture.

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