Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
20 Cards in this Set
- Front
- Back
|
What does TSI stand for?
|
Triple Sugar Iron Agar
|
|
|
What is the purpose of TSI?
|
Test that differentiates between enterobacteriaceae
|
|
|
What is TSI test based on?
|
1. Differences in Carbohydrate fermentation patterns
2. |
|
|
TSI agar slants contain...
|
1. Lactose and sucrose in 1% concentrations; glucose in 0.1% concentration
2. Acid-base indicator: PHENYL RED |
|
|
how is TSi inoculated?
|
by means of Stab and Streak.
|
|
|
how is fermentative activities of microorganisms determined in TSI?
|
1. Red slant and yellow butt: glucose fermentation
2. Yellow slant and yellow butt w/ possible gas: lactose and/or sucrose fermentation 3. Red slant and red butt: no fermentation |
|
|
What distinguishes the slant from the butt (biochem)?
|
Slant is aerobic (exposed to air) while butt is anaerobic (no air)
|
|
|
Hydrogen Sulfide Production (TSI)
|
1. The medium also has sodium thiosulfate for H2S production, and ferrous sulfate for gas detection.
2. Blackening of butt means H2S production, which is detected by ferrous sulfate. |
|
|
Overall TSI interpretation
|
1. Slant = yellow. aerobic, with glucose ferm.
2. Slant = red. aerobic, with sucrose &/ lactose ferm. 3. Butt = yellow. Glucose ferm only read in butt. 4. Butt = no change. no fermentation, man. |
|
|
Acid/Alkaline TSI detection
|
Slant/Butt:
Yellow/Yellow = Acid/Acid Red/Yellow = Alk/Acid Red/Red = Alk/ no change Yellow/Yellow w/buble= acid/acid with gas Red/black w/buble = alk/acid w/gas and H2S |
|
|
TSI detects carb fermentation because it changes from red to yellow in the presence of acid, and acid production is a sign of fermentation.
|
yeap.
|
|
|
What test must you do before doing the API strip?
|
The oxidase test
|
|
|
API 20E is uniquely intended for
|
the identification of those nonfastidious, Gram-negative rods included in the database.
|
|
|
VP1 reagent
|
40% aqueous KOH
|
|
|
What does an API + look like?
|
Change in color
|
|
|
What does the VP test separate?
|
VP+ means it's klebsiella, enterobacter, or serratia. VP tests for acetoin production.
|
|
|
What does the indole test test for?
|
Indole production
|
|
|
How long do we incubate TSI & API?
|
18-24 hours at 37C
|
|
|
What does the Indole test test for?
|
It tests for degradation of the amino acid tryptophane. The end product of this hydrolysis is called Indol.
It is used to finger E. Coli. The positive means |
|
|
What, very specifically, is the biochem of the VP test?
|
It is the result of a red colored complex, acetylmethylcarbinol (acetoin) formed from glucose fermentation.
|
