Discuss the virulence characteristics of Escherichia coli strains that cause disease.

Discuss the virulence characteristics of Escherichia coli strains that cause disease.

Expert Solution

Enterotoxigenic E.coli ( ETEC) : causes Diarrhoea in humans, pigs, sheep etc

It uses FIMBRIAL ADHESINS to bind enterocyte cells in the small intestine. It produces two toxins: LT toxin( larger) and ST toxin ( smaller). These strains are non- invasive. It is the main cause for traveller's diarrhoea.

Enteropathogenic E.coli (EPEC) : causes Diarrhoea. Molecular mechanisms are different. They don't have LT and ST toxin. They use Intimin(adhesin) to bind the intestinal cells. They are moderately invasive.

Enteroinvasive E.coli ( EIEC) : it causes shigellosis like syndrome. High fever and profuse diarrhoea are also caused.

Entetohemorrhagic E.coli (EHEC): it causes bloody diarrhoea, sudden kidney failure and hemolytic uremic syndrome. Bacterial fimbriae are used for the attachment. It is also moderately invasive.

Enteroaggregative E.coli (EAEC): only found in humans. Fimbriae are aggregates in tissue culture cells. It binds to the intestinal mucosa causing watery diarrhoea. No fever. They are non invasive. They produce hemolysin and ST enterotoxin.

Adherent invasive E.coli (AIEC): this is also found only in humans. They invade intestinal epithelial cells and replicate intracellularly.

gladiator answered 2 years ago

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