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Related Flashcards
Cards In This Set
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What are the 6 main virotypes of E.coli?
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ETEC - Enterotoxigenic E.coliEAEC - Enteroaggregative E.coliEPEC - Enteropathogenic E.coliEHEC - Enterohemorrhagic E.coliDAEC - Diffusively Adhesive E.coliEIEC - Enteroinvasive E.coli
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Which serotype(s) cause dysentery & haemolytic uremic syndrome (HUS)?
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EIEC (Enteroinvasive E.coli) causes dysenteryEHEC (Enterohemorrhagic E.coli) causes HUS
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Which serotypes cause diarrhea & which ones within these serotypes cause traveler's diarrhea?
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EAEC (Enteroaggregative E.coli) and ETEC (Enterotoxigenic E.coli) cause traveler's diarrhea specifically and EPEC (Enteropathogenic E.coli), EHEC (Enterohemorrhagic E.coli), and DAEC (Diffusively Adhesive E. coli) cause diarrhea in general.
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What is the order of the GI tract from stomach down and what bacteria are present in each?
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Stomach - lactobactilli > duodoenum - Enterococci & Lactobacilli > jejunum - Enterococci & Lactobacili > ileum - Enterococci & Lactobacili > colon - Enterobacteria, Clostridia, & Lactobacili
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Which areas of the GI tract absorb or secrete fluid?
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Secretion - gastric, pancreatic, bile, & jejunumAbsorption - jejunum, ileum, & colon
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How does diarrhea benefit enteric pathogens?
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It aids in their dissemination into the environment and new hosts
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Diarrhea results from an imbalance of what in the body?
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An imbalance of absorption and secretion of ions and solute across the gut epithelium which is what causes water to follow ions across the epithelium in an attempt to restore appropriate ion concentrations.
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What are some of the characteristics of small bowel diarrhea?
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-Uncommon to have fecal leukocytes-Uncommon to have blood in diarrhea-Large volume-Less frequent-tends to dehydrate-periumbilical cramps
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What are some of the characteristics of large bowel diarrhea (dysentery)?
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-Common to have fecal leukocytes-common to have blood in diarrhea-small volume-very frequent-less chance of dehydration-hypogastric cramps and tenesmus
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What are the causative agents of small bowel diarrhea?
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Enterotoxigenic gram negative baciliViruses (epithelial replication)Giardia lambia
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What are the causative agents of large bowel diarrhea (dysentery)?
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ShigellaCampylobacterSalmonellaInvasive E.coli
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How and when does E. coli normally colonize an infant's GI tract?
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Within 40 hours of birth through food or water or by individuals handling the child it adheres to the mucus of the large intestine.
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What causes E.coli to no longer be commensuals?
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Acquisition of genetic elements encoding virulence factors.
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What are the 5 different classification schemes for E.coli?
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1 - O anitgen (LPS) serogrouping2 - H antigens (flagella) serotyping3 - K antigens (capsular polysaccharide) subtyping4 - Virotypes (virulence phenotypes)5 - pathotypes (pathogenesis phenotypes) eg. ETEC, EPEC, EHEC, etc.
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Which classification has over 160 serotypes? and which serotype is the most common?
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K anitgen (capsular polysaccharide) subtypingof which 0157:H7 is the most common
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