sterilization and Disinfectio (2).pptxSgHGfJG

Sterilization

1. Sterilization and disinfection

2. Sterilization Is complete freeing of an article from all living organisms including bacteria and their spore toxin,viruses , fungi and their spores. Absolute term Physical methods <

3. Disinfection Chemical is partial removing of microorganism or inhibition of microorganism Relative term

4. Sterilization by heat: - moist heat - In which water is used - coagulation or denaturation of protein Dry heat -No water - Oxidation of cell

5. 1- Heat Dry Moist 1.Red heat 3.Hot air oven 2.Flaming 4.Incineration 1.Above 100C 2.At 100C 3. Below 100C

6. Dry heat Red heat Flaming Hot air Oven Incineration

7. Red heat: Articles such as bacteriological loops, straight wires, tips of forceps By holding them in Bunsen flame till they become red hot Flaming: This is a method of passing the article over a Bunsen flame mouth of test tube,culture media, flasks, glass slides and cover slip

8. How to use the hot air oven 160 c 60 min (holding time) Metals (forceps, scissors, glassware (such as Petri-dishes, pipettes, flas ks, swabs, oils, grease, petroleum jelly How to test the efficiency of the hot air oven: 1- Brown’s tube NO.3 Contain chemical substance with red solution ,if sterilization is proper it will changed into green 2- Adhesive tape At the end of sterilization the lines In the tape change from coulerless or whit Into black

9. Destroying=burning animal carcasses, pathological material,

10. Moist heat Above 100 ⁰c Below 100 ⁰c At 100 ⁰c

11. Below 100 ⁰c Pasteurizations of milk Milk borne pathogens flash method 71 ⁰c – 15 sec Holder method 63 ⁰c -65 ⁰c for 30 min Quick cooling to 13 ⁰c

12. Vaccine bath: 60oC for one hour

13. At 100 ⁰c: 1. boiling at 100 ⁰c Kills only non sporing bacteria Steaming at 100 ⁰c Arnold’s, Koch’s steamers - single exposur -90 min - intermittent exposur ( Tyndallization ): Exposur to the steam of boiling water (100 -30 min) for three succesive days Kills both sporing and non – sporing bacteria

14. Above 100 ⁰c - Autoclave Principle : Heat under pressure 121 c 15 b/I 15 min How to use the autoclave How to test the efficiency of autoclave: 1- brown’s tube NO.1 2- Adhessive tabe 3- Biological (Bacillus sterothermophilus )

15. Disinfection Chemical is partial removing of microorganism or inhibition of microorganism Relative term inanimate surfaces

16. Classification of disinfectants: 1. Based on consistency a. Liquid (E.g., Alcohols, Phenols) b. Gaseous (Formaldehyde vapor, Ethylene oxide) 2. Based on spectrum of activity a. High level b. Intermediate level c. Low level 3. Based on mechanism of action a. Action on membrane (E.g., Alcohol, detergent) b. Denaturation of cellular proteins (E.g., Alcohol, Phenol) c. Oxidation of essential sulphydryl groups of enzymes (E.g., H2O2, Halogens) e. Damage to nucleic acids (Ethylene Oxide, Formaldehyde)

17. Phenol and derivatives: Act by disruption of membranes, precipitation of proteins and inactivation of enzymes Alcohol : dehydrate cells, disrupt membranes and cause coagulation of protein 70% Ethanol- antiseptic on skin. Halogens: They are oxidizing agents and cause damage by oxidation of essential sulfydryl groups of enzymes. Iodine Chlorine

18. Heavy Metals:Act by precipitation of proteins _ Silver nitrate Gas - Ethylene Oxide- killing spores rapidly. plastics, syringes, disposable petri dishes , Aldehydes : damages nucleic acids. It kills all microorganisms, including spores Glutaraldehyde and 40% formaldehyde operation theatres, biological safety cabinets, wards,

19. Bacteriostasis is a condition where the multiplication of the bacteria is inhibited without killing them. Bactericidal is a condition where bacteria is killed or inactivated.

20. Assignment Define: Thermal death time Thermal death point