1. **NO DISINFECTING, NO HAND WASHING before Ex.33**
Lab 26 Goals and Objectives:
**NO DISINFECTING, NO HAND WASHING before Ex.33**
Exercise 33: Effectiveness of Alcohol as an Antiseptic
Each person do, follow supplemental packet directions p.129
Same FOUR GROUPS as previous lab
Exercise 31: Lethal Effect of UV Light
Score plates (+++, ++, +, -) for growth using control side of each plate as +++ for comparison; record on class sheet
Exercise 61: Temperature Lethal Effects
Score plates + or - for growth using control for comparison:
record data on class sheet, Record combined data
Exercise 34: Antimicrobial Sensitivity Testing
Four groups: each test all 8 antibiotics against one organism (assigned), two plates per organism, 4 discs per plate.
Exercise 35: Evaluation of Antiseptics
Each person try five agents against both organisms S. aureus & P. aeruginosa, SAME five agents for both to compare Gram positive vs. Gram negative

2. Effectiveness of Alcohol as an Antiseptic
Replacement Directions for Exercise 33
Effectiveness of Alcohol as an Antiseptic
Supp. page 129 A B
Divide plate into 6 sectors F C E D
A = left/non-dominant thumb dirty
B = left/non-dominant thumb again
(how many microbes removed just by touching agar?)
C = right/dominant thumb dirty
D = right/dominant thumb dipped in alcohol and allowed to dry
(how many microbes removed/killed by alcohol dip?)
E = right/dominant index finger
F = right/dominant index finger wiped with alcohol swab
(how many microbes removed/killed by swabbing with alcohol?)

3. Exercise 31: Lethal Effect of UV Light
Score plates (+++, ++, +, -) for growth using control side of each plate as +++ for comparison; record on class sheet
Why difference in amount of exposure necessary to kill Bacillus versus Staphylococcus?
UV light causes pyrimidine dimers. If SOS repair system in cell cannot keep up, mutations result in cell death

4. Exercise 61: Temperature Lethal Effects
Score plates (+, -) for growth; record on class sheet
Analyze data to determine thermal death point (TDP) and thermal death times (TDT)

5. + - 61
TDP?
TDT
@70°C?
@80°C?
@90°C?
@100°C?

6. Exercise 34: Antimicrobial Sensitivity Testing
Kirby-Bauer Method
Mueller-Hinton Agar: uniform in recipe and preparation to allow for reproducible and comparable results
2 plates of assigned organism
4 discs per plate
(8 total antibiotics to test)

7. Exercise 35: Evaluation of Antiseptics
Each person test 5 disinfectants/antiseptics against two different
organisms: Staphylococcus aureus (Gram postive) and Pseudomonas aeruginosa (Gram negative and often resistant)

8. **NO DISINFECTING, NO HAND WASHING before Ex.33**
Lab 26 Goals and Objectives:
**NO DISINFECTING, NO HAND WASHING before Ex.33**
Exercise 33: Effectiveness of Alcohol as an Antiseptic
Each person do, follow supplemental packet directions p.129
Same FOUR GROUPS as previous lab
Exercise 31: Lethal Effect of UV Light
Score plates (+++, ++, +, -) for growth using control side of each plate as +++ for comparison; record on class sheet
Exercise 61: Temperature Lethal Effects
Score plates + or - for growth using control for comparison:
record data on class sheet, Record combined data
Exercise 34: Antimicrobial Sensitivity Testing
Four groups: each test all 8 antibiotics against one organism (assigned), two plates per organism, 4 discs per plate.
Exercise 35: Evaluation of Antiseptics
Each person try five agents against both organisms S. aureus & P. aeruginosa, SAME five agents for both to compare Gram positive vs. Gram negative