Media and Stain Microbiology Study

Starch Agar

Classification: Differential medium

Ingredients: Starch, Beef Extract

Lab Usage: Detects microogranisms that break down starch

Carbohydrate Broth

Classification: Differential

Types: Dextrose, Lactose, Sucrose, Maltose

Lab Usage: Determines if the bacteria can use carbohydrates, turns carbohydrates into organic acids with or without broths

Result: red - negative, yellow - postive

Mannitol Agar

Classification: Differential and Selective

Ingredients: Beef extract, Peptone

Lab Usage: Isolates staphylococci aureus

Results: Yellow - mannitol fermenting, pink - nonfermenting colony

Eosin Methylene Blue Agar

Classification: Differential Medium and Selective

Ingredients: Lactose, Peptone, Methylene blue, Phosphate

Lab Usage: Used for gram negative bacteria against gram positive bacteria

MacConkey Agar

Classification: Differential

Ingredients: Crystal violet, Salt, Lactose, pH indicator

Lab Usage: Differs gram negative and gram positive bacteria

Results: red/pink - ferments lactose

Catalase Test

Classification: Differential

Ingredients: Hydrogen peroxide

Lab Usage: Determines staphylococci or streptococci

Oxidase Test

Classification: Differential

Ingredients: Tetra-methyl, Zinc, Magnesium

Lab Usage: Determines if organism can oxidase an enzyme

Results: if color does not change then the bacteria is negative

Coagulase Test

Classification: Differential

Ingredients: Saline

Lab Usage: Shows the difference between staphylococcus from gram negative and catalase positive

Maltose Broth

Classification: Differential

Ingredients: Peptone, Beef extract, Sodium chloride

Lab Usage: can catalyze enzymes, hydrolysis of starch

Triple Sugar Iron Agar (TSI)

Classification: Differential

Ingredients:Glucose, Sucrose, Lactose, Iron

Lab Usage: Used in lab due to its ability to ferment sugars

Results: cloudy butt indicates fermentation, production of gas will show bubbles

Citrate Agar

Classification: Differential

Ingredients: Sodium citrate, Sodium chloride, Bromothymol blue

Lab Usage: Tests for citrase

Blue - positive

Green - negative

Skim Milk Agar

Classification: Differential

Ingredients: Yeast extract, Skim milk powder, Glucose

Lab Usage: Tests for casease

Clear zone around bacteria - positive

No clear zone to be found - negative

Sulfur, Indole production, motility Agar(SIM)

Classification: Differential

Ingredients: Peptone, Iron, Sodium

Lab Usage: Indicates sulfur, indole, motility

Positive sulfur - black precipitable

Positive Indole - pink band on top after applying Kovac’s reagent

Positive motility - cloudy butt

Nutrition Gelatin

Classification: Differential

Ingredients: Animal bones, cartilage

Lab Usage: Tests for gelatinase

Turns to liquid - positive

Stays solid - negative

Urea Broth

Classification: Differential medium

Ingredients: Yeast extract, potassium phosphate, urea, phenol red

Lab Usage: Formulates test for fast urease postive organisms

Results: liquid red if positive

Blood Agar

Classification: Differential

Ingredients: 5% sheep blood cells

Lab Usage: tests the ability of organisms to produce hemolysins

CAMP Test

Classification: biochemical test

Function: tests for streptococcus agalactiae

Lab Usage: identifies bacterial organisms from patient specimens

Nitrate Broth

Classification: Differential

Ingredients: Nutrients, potassium nitrate

Lab Usage: Determines if organisms can reduce nitrate

MRVP

Classification: Interpretation

Ingredients: peptone buffers, dextrose

Lab Usage: determines which fertilization is used to utilize glucose

Results: MR - test turns red (then positive), VP - turns pink/red (then positive)

Dextrose Broth

Classification: Liquid medium

Ingredients: Dextrose, peptone

Lab Usage: determines is microbe can use glucose for carbon or energy source

Sucrose Broth

Classification: Differential

Ingredients: Sucrose. sodium chloride, peptone

Lab Usage: Used to study sucrose

Lactose Broth

Classification: Liquid medium

Ingredients: Lactose, sodium chloride, peptone

Lab Usage: Used for isolation of salmonella

Nutrient Agar

Classification: Simple media

Ingredients: Peptone, beef extract

Lab Usage: Used to test many bacterium

Colony Morphologies (8)

1. elevation (raised, flat)

2. margin (entire, filamentous)

3. size (diameter)

4. shape (circular, irregular, rhizoid)

5. opacity (opaque, transparent)

6. color (red, white, yellow, tan)

7. consistency (soft, hard)

8. surface (tough, dull, shiny, glistening)

Endospore Stain

1. smear

2. bibulous paper

3. boil water

4. place malachite green (5 min, primary stain)

5. rinse

6. safranin (2 min, control stain)

7. rinse

8. blot dry

9. results (Green - endospores, Pink - cells)

Acid Fast Stain

1. smear

2. bibulous paper

3. carbol fuchsin (6 min, primary stain)

4. bunsen burner with stain on slide

5. acid alcohol (30 sec, decolorzier)

6. rinse

7. methylene blue (1 min, counter stain)

8. rinse

9. blot

10. results (positive - pink cells, negative - blue cells)

Capsule Stain

1. india ink dot

2. mix in bacteria

3. spread across with slide

4. air dry

5. crystal violet (5 min)

6. shake it off

7. air dry

8. heat fix

9. results (white - capsule, crystal violet - cell)

Negative Stain

1. india ink dot

2. mix bacteria

3. spread across with slide

4. air dry

5. heat fix

6. results (clear - bacteria, background - stain)

Gram Stain

1. smear

2. crystal violet (1 min, primary stain)

3. rinse

4. iodine (1 min, moderant)

5. rinse

6. acid alcohol (5, sec, decolorizer)

7. rinse

8. safranin (1 min, secondary stain)

9. rinse

10. blot

11. results ( pink/red - gram negative, purple - gram positive)

Simple Stain

1. smear

2. air dry

3. heat fix

4. immersion oil

5. look under microscope

Pattern: Single Cocci

one circle

Pattern: Single Bacilli

one rod

Pattern: Diplo Cocci

two circles next to eachother

Pattern: Diplo Bacilli

two rods next to eachother

Pattern: Tetrad Cocci

Four circles in a quadrant

Pattern: Tetrad Bacilli

Four rods in a quadrant

Pattern: Strepto Cocci

a bunch of circles formed in a chain

Pattern: Stepto Baccili

a bunch of rods formed in a chain

Pattern: Staphylo Cocci

a bunch of circles random shaped and bunched together

Pattern: Staphylo Baccili

a bunch of rods random shaped and bunched together

Gram - VS Gram +

Gram - = pink/red

Gram + = purple

Label on agar should be faced

bottoms up

Simmons Citrate Agar

Classification: medium

Ingredients: citrate

Lab Usage: citrate is used as a carbon and nitrogen source

Results: test tube will turn blue if positive