Pyrrolidonyl arylamidase test: Difference between revisions
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(Created page with "* Used to identify group A streptococci and enterococci * Principle: L-naphthylamide-β-naphthylamide in the test medium is hydrolyzed, releasing free β-naphthylamide. The re...") |
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** Deep red cherry within a minute of the addition of the reagent is positive |
** Deep red cherry within a minute of the addition of the reagent is positive |
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** Yellow or orange color is negative |
** Yellow or orange color is negative |
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* Positive organisms include [[Streptococcus pyogenes]] and ''[[Enterococcus |
* Positive organisms include [[Streptococcus pyogenes]] and ''[[Enterococcus]]'' |
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Latest revision as of 11:40, 6 February 2022
- Used to identify group A streptococci and enterococci
- Principle: L-naphthylamide-β-naphthylamide in the test medium is hydrolyzed, releasing free β-naphthylamide. The reagent, N, N-dimethylaminocinnamaldehyde, is added. It joins with β-naphthylamid, if present, to form a red Schiff base.
- Procedure:
- Select 2 to 3 colonies with a loop and emulsify into PYR broth
- Incubate at 35ºC for 4 hours
- Add one drop of PYR reagent and observe for color change
- Read and record the reaction at 1 minute
- Interpretation
- Deep red cherry within a minute of the addition of the reagent is positive
- Yellow or orange color is negative
- Positive organisms include Streptococcus pyogenes and Enterococcus
