Physiological Tests Flashcards
Describe this test: Carbohydrate Fermentation Tests
(Test Description, Medium Used, Test Indicator or pH Indicator, What Negative Test Looks Like, What Positive Test Looks Like, Other Observations/Misc)
Test Description
- Carbohydrate source = energy for bacteria
- Test to see if specific carbohydrate (glc, lactose, mannitol) is used/fermented (broken down) by bacteria to produce pyruvic acid (decrease pH) and produce Co2 bubbles
Medium Used
- Glucose PRB
- Lactose PRB
- Mannitol PRB
(all contain peptones; proteins)
Test Indicator or pH Indicator
- Phenol Red (pH Indicator)
What Negative Test Looks Like
- - acid: broth red -> red/peach-orange
-> No fermentation -> no pyruvic acid -> no color change
- a gas: no bubbles (in Durham tube)
What Positive Test Looks Like
- + acid (color change): broth red -> yellow
-> Fermentation -> pyruvic acid -> pH decreases -> yellow color change
- + gas: bubbles (bubble in Durham tube)
Other Observations/Misc
- Peptones utilized = turn pink
-> Fermentation -> alkaline product -> product pH increases -> pink color change
- Record as “K”
Describe this test: Gelatinase Test
(Test Description, Medium Used, Test Indicator or pH Indicator, What Negative Test Looks Like, What Positive Test Looks Like, Other Observations/Misc)
Test Description
- Test to see if Gelatin (protein) is broken down by seeing if it secretes Gelatinase (protease/enz) to produce peptides and amino acids
Medium Used
- Nutrient Gelatin Deep Tube
Test Indicator or pH Indicator
- Gelatin (Test Indicator)
- Examine stab growth pattern in medium
What Negative Test Looks Like
- Solid -> solid
-> No gelatin breakdown -> no gelatinase (protease) -> no liquefication (peptides/amino acids)
What Positive Test Looks Like
- Solid -> liquefaction
-> Gelatin breakdown -> Gelatinase (protease) -> liquefication (peptides/amino acids)
Other Observations/Misc
- Record stab growth pattern (growth from top of tube to deep layers) under Gelatin Deep
Describe this test: Amylase/Starch Hydrolysis Test
(Test Description, Medium Used, Test Indicator or pH Indicator, What Negative Test Looks Like, What Positive Test Looks Like)
Test Description
- Test to see if bacteria breakdown starch/amylose (polysacch.) by secreting amylase (enz) to produce glucose
Medium Used
- Starch Agar Plate
Test Indicator or pH Indicator
- Iodine Solution (Test Indicator)
What Negative Test Looks Like
- No clear halo
-> Iodine solution + starch = dark brown color/no halo -> stays brown -> starch present -. no glc/amylase made
What Positive Test Looks Like
- Clear halo around bacterial growth
-> Iodine solution + starch = dark brown color/ no halo -> turns clear/glows -> no starch present; broken down -> glc/amylase made
Other Observations/Misc
- x
Describe this test: Urease Test
(Test Description, Medium Used, Test Indicator or pH Indicator, What Negative Test Looks Like, What Positive Test Looks Like, Other Observation/Misc)
Test Description
Medium Used
Test Indicator or pH Indicator
What Negative Test Looks Like
What Positive Test Looks Like
Other Observations/Misc
Describe this test: Catalase Test
(Test Description, Medium Used, Test Indicator or pH Indicator, What Negative Test Looks Like, What Positive Test Looks Like)
Test Description
- Test to see if bacteria produces catalase (enz) by adding hydrogen peroxide (H2O2; toxic) to isolated colony in TSA plate
Medium Used
- TSA plate
Test Indicator or pH Indicator
- H2O2/Hydrogen peroxide (Test Indicator)
What Negative Test Looks Like
- No bubble produced
-> H2O2 (toxic) -> no catalase -> no detoxification of H2O2 -> no water/O2 gas -> no bubbles
What Positive Test Looks Like
- Bubbles produced (~5 sec)
-> H2O2 (toxic) -> produces catalase -> detoxify H2O2 -> breakdown into water/O2 gas -> bubbles
Other Observations/Misc
- x
Describe this test: Oxidase Test
(Test Description, Medium Used, Test Indicator or pH Indicator, What Negative Test Looks Like, What Positive Test Looks Like)
Test Description
- Test to see if bacteria produce cytochrome C oxidase (enz) by adding oxidase reagent to isolate colony TSA plate/swab
Medium Used
- TSA Plate/Swab
Test Indicator or pH Indicator
- Oxidase reagent (Test Indicator)
What Negative Test Looks Like
- No purple colony
-> Oxidase reagent -> no cytochrome C oxidase -> electron of ETC not oxidized -> no purple
What Positive Test Looks Like
- Purple colony (~15 sec)
-> Oxidase reagent -> produces cytochrome C oxidase -> electron of ETC oxidized -> purple
Other Observations/Misc
- x
Describe this test: Indole Test
(Test Description, Medium Used, Test Indicator or pH Indicator, What Negative Test Looks Like, What Positive Test Looks Like, Misc)
Test Description
- Test to see if bacteria produce tryptophanase (enz) to breakdown tryptophan (AA) into indole
Medium Used
- Tryptone Broth
Test Indicator or pH Indicator
- Kovac’s Reagent (Test Indicator)
What Negative Test Looks Like
- No red ring/coloration (yellow)
-> Kovac reagent -> no presence of indole -> no combination -> no color change
What Positive Test Looks Like
- Red ring/coloration (yellow)
-> Kovac reagent -> Indole present -> combines -> color change yellow to red
Other Observations/Misc
- No shake
Describe this test: Methyl Red Test
(Test Description, Medium Used, Test Indicator or pH Indicator, What Negative Test Looks Like, What Positive Test Looks Like, Misc)
Test Description
- Test to see if bacteria can breakdown glucose into mixed acids and gases (which glucose fermentation pathway is being used?; uses mixed acid fermentation pathway?)
Medium Used
- MR-VP Broth (contains glucose)
Test Indicator or pH Indicator
- Methyl Red reagent (pH indicator)
What Negative Test Looks Like
- No color change (yellow)
What Positive Test Looks Like
- Color change (yellow -> red)
Other Observations/Misc
- Shake
Describe this test: Simons Citrate Test
(Test Description, Medium Used, Test Indicator or pH Indicator, What Negative Test Looks Like, What Positive Test Looks Like, Other Observations/Misc)
Test Description
Medium Used
Test Indicator or pH Indicator
What Negative Test Looks Like
What Positive Test Looks Like
Other Observations/Misc
Describe this test: Hydrogen Sulfide Test
(Test Description, Medium Used, Test Indicator or pH Indicator, What Negative Test Looks Like, What Positive Test Looks Like, Other Observations/Misc)
Test Description
Medium Used
Test Indicator or pH Indicator
What Negative Test Looks Like
What Positive Test Looks Like
Other Observations/Misc
