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14 Cards in this Set
- Front
- Back
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What does corynebacterium look like?
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It is gram positive pleomorphic rods, often club shaped bacteria - usually appear as Chinese characters (V and L)
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What is the one major pathogen of Corynebacterium?
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C. dipptheriae - other species are normal flora of the skin and mucus membranes
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This species of Corynebacterium causes upper respiratory disease with systemic toxemia and chronic skin lesions. It can also be normal flora of the URT because there are many non-toxogenic strains.
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C. diphtheriae
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This is the term given to the non-disease causing organisms in the genus Corynebacterium that are normal flora in most people and disease is typically only seen in immunocompromised.
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Diptheroids
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Has cell wall glycolipids, with shorter chain length, is not acid fast, and appears as pleiomorphic club shaped rods.
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C. diphtheria
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This lethal toxin is essential for disease production and is located on the tox gene on a phage genome.
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Diphtheria Toxin
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What cells are particularly sensitive to diphtheria toxin?
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Heart cells
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How does diphtheria toxin work?
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Causes inhibition of protein synthesis and cell death
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How do you prevent infection with C. diphtheria?
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There is a vaccine - antibody against the toxin provides complete protection
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How is it possible for C. Diphtherae to be normal flora?
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It is usually the non-toxogenic strains that are common on the skin and URT.
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How does C. diphtherae invade and cause disease?
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It is a local infection with systemic toxemia - colonization of the URT in a susceptible person with a toxin producing strain
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How does the toxin in diphtheria act to invade the blood stream?
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The toxin causes necrosis of mucosa and invades the bloodstream and the bacteria remain localized on the surface while the toxemia causes necrosis of the heart muscle and other tissue
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How does diphtheria typically present?
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There is a 2-6 day incubation followed by pharyngitis, slight fever and malaise. There is a greyish white exudate (pseudomembrane) on the throat and marked edema of the entire neck. There is respiratory obstruction that can be fatal.
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What kind of vaccine is there against diphtheria?
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There is a toxoid of diphtheria toxin which is immunogenic but non-toxic.
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