**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

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?)

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

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)

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

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)

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)

**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