Disinfectants prevents spread of disease. Kills harmful bacteria and viruses. Reduce the number of pathogens present in the environment. Reduces risk of infection to patients and health-care personnel. Prevent transmission of infections among patients and health care professionals.

1. Disinfection
By
Dr Kamala DN

2. Overview
1. Disinfection
2. Methods of disinfection
3. Classification of disinfectants
4. Properties of an ideal disinfectant
5. Advantages
6. Uses
Disinfection

3. Definition:
• Disinfection is a process that destroys most pathogenic organisms but not bacterial spores..
• Surface disinfection is a method to inactivate pathogens on inanimate surfaces.
• Sterilization is a process by which all living microorganisms , including viable spores are
destroyed or removed from article, surface or medium.
• Dr Kamala DN
Disinfection
Dr Kamala DN

4. Properties
Properties of an ideal disinfectant
Broad spectrum Wide antimicrobial spectrum.
Fast-acting contact
time
Rapid kill microorganisms
Not affected by
physical factors
Active in the presence of organic matter (e.g., blood, sputum, etc.)
Nontoxic Non-allergenic, non- irritative or non-corrosive
Safe on surfaces Should not corrode or damage instruments and equipment (e.g.,
rubber, plastic, cloth, metal, etc.)
Residual effect on
treated surfaces
Should keep surface wet long enough kill/contact times with a single
application

5. Methods of disinfection
Sterilization/
Disinfection
Physical
method
Chemical
method
Gases
Dr Kamala DN

6. Methods of disinfection
Physical
Drying
Heat
Filtration
Radiation
UV radiation
Gas
Ethylene oxide
Formaldehyde
Plasma
Dr Kamala DN

7. Chemicals
Acids & alkalies
Oxidising agents
Heavy metals
Surface active agents
Dyes
Chemicals Method
Alcohols
Aldehydes
Phenols
Quaternary
ammonium
compounds
Halogens
Methods of disinfection
Dr Kamala DN

8. Types of Disinfectants
Chemical agents Examples
Alcohols Ethyl alcohol ,Isopropyl alcohol
Biguanides Chlorhexidine
Aldehyde Formaldehyde, Glutaraldehyde ,Ortho- phthaldehyde
Phenols Cresol, Lysol , Chloroxylenol ( Dettol)
Oxidising agents Hydrogen peroxide, Parcetic acid
Heavy metals(Salts) Mercuric chloride, Copper salts
Surface active agents Detergents and Soaps
Dyes Aniline dyes, Acridine dyes, Gentian violet
Halogens Iodine , Chlorine
Quaternary ammonium compounds Cetrimide

9. Classification :
Based on consistency
a. Liquid (E.g., Alcohols, Phenols)
b. Gaseous (Formaldehyde vapor, Ethylene) oxide)
Based on spectrum of activity
a. High level
b. Intermediate level
c. Low level
Classification
Dr Kamala DN

10. Based on Mechanism of Action
Oxidation of bacterial protoplasm
e.g. H202, Halogens, potassium permanganate
Coagulation (denaturation) of proteins
e.g. Phenols, chlorhexidine, alcohols, aldehydes
Increasing permeability of bacterial cell membrane
e.g. Cetrimide, soaps.
Classification
Dr Kamala DN

11. Benefits
• Prevents spread of disease.
• Kills harmful bacteria and viruses.
• Reduce the number of pathogens present in the environment.
• Reduces risk of infection to patients and health-care personnel.
• Prevent transmission of infections among patients and health care professionals.
Advantages
Dr Kamala DN

12. • Kitchens
• Hand wash
• Food industry
• Dairy industry
• Pharmaceuticals industry
• Hospitals
• Biological laboratories
• Bathroom
• Floor
Uses
Indications : Used to disinfect
Dr Kamala DN

13. Alcohol is used for sterilization and disinfection of micro-organisms . It kills bacteria, fungi and
some enveloped viruses, some resistant fungal spores remain unaffected.
Examples: Ethyl alcohol, isopropyl alcohol and N-propanalol
Mode of action : Alcohols dissolves membrane lipids and denature protein of micro-organisms
resulting in lysis of cells.
Application : Surgical spirit and antiseptic, hand sanitizer , Surface disinfectant
Disadvantages: Skin irritant, volatile (evaporates rapidly), inflammable
Alcohols
Dr Kamala DN

14. Hydrogen peroxide is a chemical steriliant.
Mode of action :It liberates free radicals which are toxic to cells. These radicals attack on
membrane and other organelles of cells such as DNA , lipid and cause lysis of cell.
Application:. 3% Hydrogen Peroxide Solution is used for skin disinfection and deodorising wounds
and ulcers. It is used for sterilization of contact lenses , ventilators and plasma sterilization.
Disadvantages: Decomposes in light, broken down by catalase, proteinaceous organic matter
drastically reduces its activity.
Hydrogen Peroxide
Dr Kamala DN

15. Chlorhexidine is s broad spectrum antimicrobial.
• Mode of action :
Acts by disrupting bacterial cell membrane & denaturation of bacterial proteins
• Broad spectrum antimicrobial ,
• Used in for surgical scrub, neonatal bath, mouth wash & general skin antiseptic
• Most widely used antiseptic in dentistry
• 0.12-0.2% oral rinse or 0.5 -1 % tooth paste.
Chlorhexidine
Dr Kamala DN

16. Thank You…