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39 Cards in this Set
- Front
- Back
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Gastroenteritis
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incubation is 12hrs to days because it is an infection
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Food poisoining
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GI symp wiht in a few hours cause it is not an infection
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Diarrhea
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>300g of stool daily with increased liquidity and frequency
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Secretory Diarrhea
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water and ion loss, no damage
ie cholera |
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Malabsorptive diarrhea
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damage to mucosal cells inmpairs water uptake
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dysentery
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multiple, bloody, mucoid stools
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Characteristics of enterobacteriaceae
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gram negative
non-spore forming facultatively anaerobic bacilli produce acid from glu ferment reduce nitrates cytochrome oxidase negative |
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Are salmonella motile?
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yes, peritrichous flagella
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What is a good way to distinguish salmonella?
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do not ferment lactose - MacCanky agar
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What are the 3 types of salmonella that are highly adapted for humans?
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s. typhi
s. parptyphi s. sendai |
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What is the most frequent salmonellosis?
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s. typhinurium
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What types of infections does salmonella cause?
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gastroenteritis - selflimiting
systemic typhoid fever |
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How do you get salmonella?
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eating contaminated food or water
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How does salmonella colonize?
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invasion of peyers patches and enters through M cells which die leaving a gap and allows bac into the lamina propria and makes a vacuole
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What do M cells do and what disease are they important in?
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they sample the intestinal enviornment looking for Ag and are involved in salmonella and shigella
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what is the model for salmonella?
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Caco-2 cells in mice
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What is the mechanism in which salmonella and shigella enter a cell?
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Type III secretion apparatus
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What did the Type III secretion apparatus evolve from?
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flagella
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SPI 1?
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required for entry of salmonella into cells and translocates effectors across the plasma membrane
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What does SPI stand for?
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Salmonella Pahtogenicity Islands
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What are the effectors of SPI 1?
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induce ruffling
int't directly with cytoskele insert into host memb cross-link actin nucleate actin polymerization |
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SPI 2?
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required for intracellular survival of salmonella - blocks vacuole from fusing with the lysosome
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Non-typhoidal samonellae...
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#2 foodborne disease
meat, poultry, eggs, dairy infectious dose is reduced with decrease in stomach acid |
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Typhoid fever
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early - like gastroenteritis
enter M and prolif in lymph follicles fever, endotoxemia (LPS), bacteremia(exotoxin), rose spots fever can last 30 days |
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Live attenuated vaccine Ty21a for typhoid..
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reduced side rxns
6 pills booster @ 5yrs cannot be given with antibiotics!!!! |
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Vi polysaccharide capsular vaccine (typhim) for typhoid...
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good for 2 yrs
injection once |
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4 species that cause diseases in humans of shigella
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s. dysenteriae
s. flexneri s. boydii s. sonnei |
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Charactersitics of the shigella family...
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non-motile
unencapsulated oral-fecal contaminated food and water |
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What does shigella share and with what?
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toxins with invasive strains of e.coli
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Ipa?
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invasion protein antigens
infectious part of shigella |
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How does shigella get in?
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Type III
IpaB binds integrins so actin poly and depolymerizes and gets in a vacuole |
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Once inside a cell how does shigella differ from salmonella?
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they dont like being in a vacuole
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How does shigella move?
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acin polymerization and depolymerization at one pole
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What is the shigella toxin?
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A:5B
A - RNA N glycosidase B - recognizes terminal glactose residues on globotriaosylceramide (GB3) |
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What does shigella toxin part B recognize?
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terminal galactose residues on globotriaosylceramide
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What does the A subunit of the shigella toxin do?
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RNA N-glycosidase
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Stx...
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S. dysenteriae
chromosomal |
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Stx 1
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E. coli
phage or chromosomal |
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Stx 2
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E. Coli
phage - worst |
