1. Protein lysis chapter 27 Page 207 Bacteria: Medium: Escherichia coli
Staphylococcus aureus
Salmonella
Medium:
Skim milk medium
Lysine decarboxylase broth
Triple Sugar Iron (TSI)

2. Triple Sugar Iron agar (TSI)
Skim milk medium
Casein
Casein lysis (clear zone)
Triple Sugar Iron agar (TSI)
H2S
Black precipitation
Lysine decarboxylase broth
Deamination
(pH change, color change)

3. Two plates or tube (one for each type) for one group
Medium:
Skim milk medium (plate)
E. coli, S. aureus, and Salmonella
E. coli and Salmonella share the same plate
Lysine decarboxylase broth (10 mL/tube)
E. coli, Salmonella, and S. aureus
Triple Sugar Iron agar TSI
E. coli and Salmonella
Two plates or tube (one for each type) for one group

4. Skim milk agar
skim milk g
Agar g
Water one liter

5. TSI Approximate Formula* Per Liter
Beef Extract g
Yeast Extract g
Pancreatic Digest of Casein g
Proteose Peptone No g
Dextrose g
Lactose g
Sucrose g
Ferrous Sulfate g
Sodium Chloride g
Sodium Thiosulfate g
Agar g
Phenol Red mg

6. Lysine decarboxylase broth
Peptone g
Yeast extract g
Dextrose g
L-lysin g
Brocresol purple g

7. Procedures Inoculate bacteria Skim milk plate
Streak onto plate (streak four times to obtain single colony)
Lysine decarboxylase broth
Dip and shake the loop into broth
TSI
Stab 1 cm deep into the slant, then streak on the surface

8. Incubation Observation Skim milk plate TSI 37℃ Next Monday (5/10)
For lysine decarboxylase broth
Place the tubes 37℃
Keep watching on 5/11
Skim milk plate
Clear zone indicates lysis of casein
TSI
Black indicates formation of H2S
Yellow indicates fermentation of sugars and formation of acids

9. TSI
E. coli
Salmonella

10. Lysine decarboxylase broth
When the medium is inoculated with a bacterium that is able to ferment dextrose, acids are produced that lower the pH of the medium and change the color of the indicator from purple to yellow.
Lysine produce
Purple with cloudy

11. Lysine decarboxylase broth
Partial positive
Acid produce