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15 Cards in this Set
- Front
- Back
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Test results for genus Escherichia
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G- rods
motile/nonmotile strong coliform citrate - H2S - Indole + Urease - Lys/Orn decarb + Gas + KIA acid/acid |
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What are colicins and what do they do?
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cell-free substance produced by coliforms that is encoded on plasmids and inhibits other bacteria by membrane depolarization, DNA endonuclease, ribosome inactivation
Colicin E1 arrests macromolecular syn Colicin E2 inhibits DNA syn |
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What are 2 important structures assoc with E.coli?
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1. Fimbriae (pili) - type 1 binds to urinary slime, allow for adherence to intestinal wall
2. LPS "O" antigen |
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What are the 2 steps for infection by E.coli?
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1. attachment by pili to jejunum and ileum
2. enterotoxin production act on attached cells |
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Describe the LT toxin and how it effects the cells of the GI tract
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has a high molec weight, heat-labile. B subunit binds to GMI, A subunit acts by catalyzing the addition of ADP-ribose to the GS protein that controls cAMP production. inactivation of GS causes increase of cAMP which activates Cl channels, and inhibits NaCl uptake, causing cells to lose control of flow of water = diarrhea
*ETEC* |
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What is the ST toxin and how does it work?
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low molec weight, heat stable, stimulates guanylate cyclase
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ETEC
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Traveler's Diarrhea
LT and ST secretion, no dmg to mucosal epithelium Symptoms: watery diarrhea, cramps, vomiting Strains: 06, 08, 015, 020 |
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EPEC
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Infantile Diarrhea
bact cells attach to epithelial cells, causing effacing lesions symptoms: fever, malaise, vomiting, diarrhea, lrg amt of mucous with no gross blood strains: 055, 086, 0111, 0119 nosocomially acquired |
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EIEC
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Dysentery like diarrhea
bacteria invade epithelial cells symptoms: dysentery, fever, colitis. painful straining at stools with blood, mucous, and WBC's Strains: 028ac, 029, 0112ac, 0124 |
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EHEC aka VTEC aka STEC
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hemolytic-uremic syndrome diarrhea
cytotoxins stx1 (encoded on a temperate bacteriophage), like the shiga toxin, receptors found on kidney and intestinal cells. symptoms: bloody diarrhea w/out WBC's, abdominal pain, may progress to HUS strain: 0157:H7 maybe be isolated by plating on SMAC, sorbitol - |
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EAEC
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bact cells adhere to epithelial cells in a stacked-brick pattern and produce ST-like toxin
symptoms: diarrhea, fever, dehydration, uncommon abdominal pain |
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DAEC
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bact cells adhere to epithelial cells in diffuse pattern and carry gene encoding a surface fimbria F1845
Symptoms: diarrhea w/out blood or WBC's |
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What tests differentiate E. hermannii from E.coli and E. fergusonii?
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Lys dec -
orn dec + ONPG + yellow pigmented, found in wounds, sputum, feces, does not cause infection |
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What tests differentiate E. fergusonii?
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lys +
orn + recovered from blood, gall bladder, urine, feces, significance unknown |
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How do you treat E.coli infections?
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UTI - sulfonamides, ampicillin
sepsis- gentamicin neonatal meningititis- ampicillin, gentamicin |
