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16 Cards in this Set
- Front
- Back
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What is Shigella?
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Nonmotilie, nonlactose-fermenting, oxidase-negative, G- enteric rods.
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What is teh reservoir for Shigella?
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Humans only, there is no other animal reservoir
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How is Shigella transmitted?
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Fecal-oral and food-borne transmission
Four F's: fingers, flies, food, feces |
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What does it mean Shigella need a low dose to be infectious?
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Even a low number of organisms can cause disease if ingested (-200)
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Is the infectious dose low or high for Shigella?
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Very Low
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How many different serotypes of Shigella exist?
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40 serotypes are organized into 4 species based on the polysaccharide O antigen.
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What Shigella serogroup is the most common in the US?
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S. sonnei
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What toxin is associated with Shigella?
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Shiga toxin, which is only produced by S. dysenteriae serotype 1.
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What is shiga toxin?
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An exotoxin with cytotoxic properties
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How does Shigella cause disease?
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Invades and destroys the mucosa of the large intestine, but does not cause bacteremia.
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What disease does Shigella commonly cause?
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Dysentery
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What are the symptoms of this disease?
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Blood diarrhea, mucus, and painful abdominal cramping; seizures in children.
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How long do symptoms of dysentery last?
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Untreated dysentery resolves in 1 week.
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What selective agar can be used to identify Shigella?
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Hektoen agar
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What is Hektoen agar?
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Agar that can differentiate on the basis of lactose fermentation and hydrogen sulfide production and which contains bromthymol blue pH indicator and bile salts for inhibition of G+ organisms.
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What is the treatment for Shigella dysentery?
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Ciprofloxacin or azithromycin can reduce th duration of the illness, but concerns about resistance and increased frequency of hemolytic uremic syndrome have made treatment controversial.
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