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21 Cards in this Set
- Front
- Back
Gram stain, shape
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Negative, rod
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Aerobic or anaerobic or???
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Facultative aerobic
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3 groups??
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1) Humans only
2) Adapted for a particular species 3) Paratyphoids - no particular host preference... Infects both humans and animals |
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2 species are??
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S. bongori
S. enterica |
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S. bongori infects?
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Cold blooded animals
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S. enterica infects?
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Mostly warm blooded
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Naming of salmonella (3 things)
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1) Disease syndrome or animal first isolated from
2) Place first reported 3) Antigenic formula |
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Antigenic structure (Kauffmann-White scheme)
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O-somatic capsule
Vi-Capsular antigen H (phases 1 and 2) Flagellar antigen -heat labile |
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Phase variation (antigenic) is?
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H antigen exists in 2 phases. An indiv bacterial cell can have flagella in either phase 1 or 2. Bact originally in one phase can switch during multiplication.
Non-motile strains don't demonstrate phase variation Need to ID both phases. |
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H-O variation
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Loss of H antigen or flagella
Usually 1 direction only Motile -> Non motile Spontanous change is rare and often irreversible Genetic material for enzyme that synthesizes flagella is lost/altered. |
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S-R variation
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Smooth to rough form
Known to occur in practically all bacteria Gradual change Rough organisms give non specific agglutination. Low virulence - can be vax strain. No change in flagellar antigen |
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O variation
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change in lipopolysaccharides on surface
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V-W variation
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loses/changes outernost polysaccharide layerantigen
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Salmonella ID - selective media, test
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MacConkey, Brilliant Green, XLD
API, TSI, Indole, urea |
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MacConkey
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Tan (non lactose fermentor)
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Brilliant Green
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red (like Citrobacter, E.coli is grn)
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XLD
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Purple (Citrobacter/E. coli grn)
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Pathogenesis
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Ingestion
Colonization of lower intestine (ilieum and cecum) Mucosal invasion (cytotoxin) Acute inflammation (ulceration, prostoglandin, enterotoxins, cytokines) Activation of adenyl cyclase (increase cAMP) Fluid production (lg and sm bowel) Diarrhea |
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Virulence
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Antigenic phaes variation
sequestration of nutritional factors Resistance to serum killing Antimicrobial resistance Pathogenicity islands |
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Leading cause of ??
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Human foodborne illness worldwide (1-5 million cases in US yearly
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Human salmonella serotypes
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S paratyphi A
S paratyphi B S paratyphi C S typhi Also, non-host adapted Salmonella strains |