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24 Cards in this Set
- Front
- Back
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Name me 4 descriptions of alpha H strep
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transcluscent
maybe mucoid grey/white concave colonies |
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If Optochin Taxo P is no zone/R, what organism is it?
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Viridians Group of Streptococci
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If Optochin Taxo P is zone/S, >14mm, Bile Solubility test insoluble, what organism is it?
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Viridians Group of Streptococci
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If Optochin Taxo P is zone/S, >14mm, Bile Solubility test soluble, what organism is it? What special feature does it have?
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Streptococcus Pneumonia
colonies flatten/disappear |
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What is AH?
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partial hemolysis of RBC producing methemoglobin which causes greenish media
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Name me two types of AH?
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Streptococci pneumoniae
Viridians Group of Streptococci pneumonia |
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Describe Strep pneumoniae microscopic characteristics (4).
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-gpc, lancet pairs, short chains
-encapsulated strains exhibit non-staining halo -gram variable with age (ie stain pink or purple -minor pleomorphism |
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Describe Strep pneumoniae macroscopic characteristics (4).
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-aH, translucscent, grey
-autolytic enzymes cause centre to collapse (concave colonies) -very mucoid if encapsulated strain |
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Is it not necessary to do catalase test for aH strep? Why?
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No, b/c its used to differentiate staph and strep and there are no aH staph.
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What is impregnanted in the Taxo P disc? What temp is it incubated at & when is it S?
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-5 ug of ethylhydrocupreine hydrocholoride
-incubate CO2 35C - > 14mm |
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When do we do a bile solubility test?
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when the zone of inhibition is less then 14mm to confirm a positive for Strep pneumoniae
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Describe the bile solubility test
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-Strep pneumo lysed by bile salt sol'n (sodium deoxycholate), which accelarates autolyic process
-Viridians don't lyse -use FRESH colonies -incubate with lid open at 35C in airbient air |
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Describe the bile solubility test results
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soluble: colonies flat concave = strep pneump
insoluble: colonies intact, viridians |
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What kind of Cell wall does strep pneuo have
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C-polysaccharide
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Is strep pneu lancefield groupable?
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no
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Name me two types of serolgical tests that can be done on strep pneumoniae
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Quellung rxn (capsular microppt test): antibodies bind to the capsule of Streptococcus pneumoniae and thus allow it to be visualized under a microscope. If positive, the capsule becomes opaque and appears to enlarge/swollen and RI of capsule changes
Polyclonal co-agglutination tests: latex agglut |
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what is the normal flora of strep pneumo
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nasopharynx
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what is the main virulence factor? And how does it work?
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C-polysacharide capsule - resists opsonization and phagocytosis
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Who is most likely to get infection?
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-Compromised patients
-elderly and young |
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Infants and children: what clinical sickeness can they aquire (5)
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-pneumonia,
otitis media, bacterimea, meningites, pink eye conjunctivits |
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What is the drug of choice for Strep pneumo? For resistant ones?
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Pen G
For resistant ones - erythro, clind, tetra, chloro |
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In the lab, what would use to test susceptlibiltiy of strep
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Non-invasive - Pencillian (use oxcacillin)
Invavisive infection: oxacillin, clind, erythro |
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Name me 2 vaccines again strep pneumo
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-one is against the polysacharide capsule Ag for high risk groups
-heptvalent |
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Another way to preven strep pneu
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Chemoprophylaxis refers to the administration of a medication for the purpose of preventing disease or infection. Antibiotics, for example, may be administered to patients with disorders of immune system function to prevent bacterial infections (particularly opportunistic infection).
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