Week Two Medium Flash Cards

Front 1

Oxidation-Fermentation (OF) Test

Back 1

Front 2

Oxidation-Fermentation (OF) Test:

Medium Recipe

Back 2

Front 3

Oxidation-Fermentation (OF) Test:

Purpose

Back 3

The OF test is used to differentiate bacteria based on their ability to oxidize or ferment specific sugars. It allows presumptive separation of the fermentative Enterobaderiaceae from the oxidative Pseudomonas and Bordetella, and the nonreactive Alcaligenes and Moraxella.

Front 4

Oxidation-Fermentation (OF) Test:

Visual of Results

Back 4

Front 5

Definition: Fermentation Tests

Back 5

Is the metabolic process by which an organic molecule acts as an electron donor (becoming oxidized in the process) and one or more of its organic products act as the final electron acceptor (FEA).

Includes hydrolysis of disaccharides prior to the fermentation reaction. Thus, a "lactose fermenter" is an organism that splits the disaccharide lactose into the monosaccharides glucose and galactose and then ferments the monosaccharides.

Front 6

Phenol Red Broth (PR) Test: Purpose

Back 6

PR broth is used co differentiate members of Enterobaderiaceae and to distinguish chem from ocher Gram-negative rods. It also is used to distinguish benveen Grain-positive fermenters, such as Streptococcus and Lactobacillus species.

Front 7

Phenol Red Broth (PR) Test:

Medium Recipe

Back 7

Front 8

What is Phenol Red?

Back 8

Differential test medium prepared as a base to which a carbohydrate is added.

Front 9

Phenol Red Indication:

(A) Yellow (Acid) + Gas

(B) Yello (Acid) no Gas

(C) Orange (neutral) no gas

(D) Red (alkaline) no gas

Back 9

(A) Fermentation of Sugar

(B) fermentation of Sugar

(C) Oxidation of Sugar

(D) Oxidation of proteins

Front 10

What causes color change in Phenol Red Broth?

Back 10

Acid production from fermentation of the carb lowers the pH below the jeitralnrange if the indicator (Phenol Red) and turns the color Yellow.

Delamination of amino acids supplied by pepitone marks an alkine reaction via the production of NH3. This turns the broth Pink to Magenta.

Front 11

Methyl Red and Voges-Proskauer (MR-VP) Tests

Back 11

It's two tests combined into one: Methyl Red (MR) and Voges Proskauer (VP)

Front 12

Methyl Red and Voges-Proskauer (MR-VP) Tests: Medium

Back 12

Composed of Peptone, Glucose, and Phosphate Buffer.

The Peptone and Glucose supply protein (via Nitrogen) and fermentable carbs.

Potassium phosphate resists pH change in medium.

Front 13

Methyl Red and Voges-Proskauer (MR-VP) Tests: the MR portion

Back 13

Is designed to detect organisms performing mixed acid fermentation which overcomes the phosphate buffer in the medium and lowers the pH.

- Red color = (+) results (pH 4.4)

- Orange olor = (-) or unconfirmed

- Yellow color = (-)

Front 14

Methyl Red and Voges-Proskauer (MR-VP) Tests: the VP portion

Back 14

Detects organims able to ferment glucose. The resulting acid is converted to Acetoin and 2,3-butamediol.

VP reagent oxidizes acetoin and 2,3-butamediol, which in turn reacts with grenadine nuclei from proton to produce a red color.

(+) VP test = Red color

(-) VP test = No color change (or development of Copper Color)

Front 15

Catalase Test

Back 15

When Hydrogen Peroxide is added to a Catalse-positive culture, oxygen bubbles form immediately.

If no bubbles form, then the organism is Catalase-negative.

Front 16

Catalase Test: Results Interpretation (1)

Back 16

Front 17

Catalase Test: Results Interpretation (2)

Back 17

Front 18

Oxidase Test

Back 18

Designed to detect the presence of Cytochrome C Oxidase.

Chromogenic reducing agents are chemicals that develop color as they become oxidized.

Front 19

Oxidase Test: Results Interpretation

Back 19

Front 20

Oxidase Test:

Why must results be read during first 20 sec after application?

Back 20

Reagents used for this test are unstable and may oxidize independencly shortly after they become moist. Therefore, it is important to take your readings within the recommended time (usually 20 seconds).

Front 21

Nitrate Reduction Test:

Medium

Back 21

Front 22

Nitrate Reduction Test:

Results Interpretation

Back 22

Front 23

Nitrate Reduction Test:

Graphic

Back 23

Front 24

Nitrate Reduction Test: Info

Back 24

Occurs in two parts, no color indicators are used in first half.

If gas forms in tube = (+) result

- Signals Nitrate Reductase Activity.

If no gas, then add Reagent A and B.

- Red Color change = Organism reduced nitrate to nitrite.

- No Color change = add Zinc.

After Zinc was added

- Red Color change = Nitrate was NOT reduced by organism.

- No Color Change = organism reduced beyond Nitrite.

Front 25

Nitrate Reduction Test: Application

Back 25

Virtually all members of Enterobacteriaceae perform a one-step reduction of nitrate to nitrite. The nitrate test differentiates them from Gram-negative rods that either do not reduce nitrate or reduce it beyond nitrite to N2 or other compounds.

Front 26

Oxidation Fermentation Test:

Symbol

Back 26

O-F

Front 27

Oxidation Fermentation Test:

Substrate

Back 27

Sugar

Front 28

Oxidation Fermentation Test:

Reaction

Back 28

Ferm. Or Oxid.

Front 29

Oxidation Fermentation Test:

Indicator

Back 29

Bromothymol Blue

Front 30

Oxidation Fermentation Test:

Positive Result

Back 30

Ferm. - Yellow

Oxid. - Blue

Front 31

Oxidation Fermentation Test:

Negative Result

Back 31

Green

Front 32

Oxidation Fermentation Test:

What it Isolates

Back 32

Differentiates between Gram (-) aerobic/anaerobic.

Front 33

Phenol Red Broth:

Symbol

Back 33

PRB

Front 34

Phenol Red Broth:

Substrate

Back 34

Sugar

Front 35

Phenol Red Broth:

Reaction

Back 35

Ferm. + Gas

Front 36

Phenol Red Broth:

Indicator

Back 36

Phenol Red

Front 37

Phenol Red Broth:

Positive Results

Back 37

Yellow - Ferm.

Bubble in Durham tube - Gas Prodution

Front 38

Phenol Red Broth:

Negative Results

Back 38

Red- Pink broth; No bubble.

Front 39

Phenol Red Broth:

What it Isolates

Back 39

Differentiate between Gram + fermenters.

Front 40

Methyl Red - Voges Proskauer Test:

Symbol

Back 40

MRVP

Front 41

Methyl Red - Voges Proskauer Test:

Substrate

Back 41

Glucose

Front 42

Methyl Red - Voges Proskauer Test:

Reaction

Back 42

Mixed Acid Ferm.

Front 43

Methyl Red - Voges Proskauer Test:

Indicator

Back 43

None.

Front 44

Methyl Red - Voges Proskauer Test:

Positive Results

Back 44

MR - Red color; VP - Red Color

Front 45

Methyl Red - Voges Proskauer Test:

Negative Results

Back 45

No color change.

Front 46

Methyl Red - Voges Proskauer Test:

What it Isolates

Back 46

Differentiate between Enterobacteriacaea.

Front 47

Catalase Test:

Symbol

Back 47

None.

Front 48

Catalase Test:

Substrate

Back 48

H2O2

Front 49

Catalase Test:

Reaction

Back 49

Catalase Enz. Rxn.

Front 50

Catalase Test:

Indicator

Back 50

None

Front 51

Catalase Test:

Positive Results

Back 51

Bubbles

Front 52

Catalase Test:

Negative Results

Back 52

No bubbles

Front 53

Catalase Test:

What it Isolates

Back 53

Differentiate Mirococcacus from Streptococcus.

Front 54

Oxidase Test:

Symbol

Back 54

None

Front 55

Oxidase Test:

Substrate

Back 55

Cytochrome - C Oxidase

Front 56

Oxidase Test:

Reaction

Back 56

Reduction

Front 57

Oxidase Test:

Indicator

Back 57

None.

Front 58

Oxidase Test:

Positive Results

Back 58

Purple - dark blue

Front 59

Oxidase Test:

Negative Results

Back 59

No color change.

Front 60

Oxidase Test:

What it Isolates

Back 60

ID Neisseria or Moraxella sp.

Front 61

Nitrate Reduction Test:

Symbol

Back 61

None

Front 62

Nitrate Reduction Test:

Substrate

Back 62

Nitrate

Front 63

Nitrate Reduction Test:

Reaction

Back 63

Reduction

Front 64

Nitrate Reduction Test:

Indicator

Back 64

None.

Front 65

Nitrate Reduction Test:

Positive Results

Back 65

Red - after reagents;

colorless - after zinc.

Front 66

Nitrate Reduction Test:

Negative Results

Back 66

Colorless - then pink.

Front 67

Nitrate Reduction Test:

What it Isolates

Back 67

Differentiate between Enterobacteriacaea