Lecture - Escherichia coli

Lecture - Escherichia coli - Escherichia coli 0157:H7 E....

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Escherichia coli 0157:H7 E. coli strains are a common part of the normal facultative anaerobic microflora of the intestinal tracts of humans and warm- blooded animals. Isolates are serologically differentiated on the basis of three major surface antigens: o (somatic); H (flagella) and k ( capsule). There are a total of 174 o antigens, 56 H and 80 k antigens identified.
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E. coli 0157:H7 Most E. coli strains are harmless, but a few are pathogenic and cause diarrheal disease. E. coli strains that cause disease are categorized into specific groups based on virulence properties, mechanisms of pathogenicity, clinical syndromes and distinct O:H serogroups.
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E. coli 0157:H7 These categories include: enteropathogenic E. coli strains (EPEC); enterotoxigenic E. coli strains (ETEC), enteroinvasive E. coli strains (EIEC), diffuse-adhering E. coli strains (DAEC), enteroaggregative E. coli strains (EAggEC) and enterohemorrhagic E.coli stains (EHEC).
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Enteropathogenic E. coli (EPEC) EPEC can cause severe diarrhea. Human are important reservior. The 0 serotypes are associated with illness and include 055,086, 0111ab, 0119 and others. EPEC toxin can induce the attachng and effacing (AE) lesions in cells to which they adhere can invade epithelial cells.
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Enterotoxigenic E. coli (ETEC) ETEC (serogroup o) is the major cause of infantile diarrhea in developing countries and most frequently responsible to “travelers diarrhea. ETEC colonize the small intestine by fimbrial colonization factors (CFA/1 and CFA/II) and produce a heat-labile or heat-stable toxin that elicits fluid accumulations and a diarrheal response. Humans are the reservoir.
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Enteroinvasive E. coli (EIEC) EIEC causes diarrhea and dysentery similar to that caused by Shigella spp. by invading and multiplying within colonic epithelial cells. The invasive capacity of EIEC is controlled by a large plasmid that encodes for several outer membrane proteins. The site of localization is the colon epithelial cells. Reservoir is humans and serogroup o124 is frequently associated with disease.
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Diffuse-adhering E. coli (DAEC) DAEC have been associated with diarrhea in children in Mexico. Causes mild diarrhea and are identified by a characteristic diffuse-adherent pattern of
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Lecture - Escherichia coli - Escherichia coli 0157:H7 E....

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