Microbial Control: Sterilization, Disinfection, and Antisepsis PDF

MICROBIAL CONTROL Sterilisation, Disinfection, and Antisepsis Dr. Abdulrahman Alsultan 7 / 11 / 2024 1  Learning Objectives The purpose of sterilization, disinfection and antisepsis The principles of sterilization, disinfect...

MICROBIAL CONTROL Sterilisation, Disinfection, and Antisepsis Dr. Abdulrahman Alsultan 7 / 11 / 2024 1  Learning Objectives The purpose of sterilization, disinfection and antisepsis The principles of sterilization, disinfection and antisepsis The most important methods for sterilization, disinfection and antisepsis 2 What is the main purpose of sterilization, disinfection and antisepsis control of infections. 3  Sterilization  Sterilisation is the process that eliminates or kills all forms of microbial life.  It is the total destruction of all microbes including the more resilient forms such as spores  This can be achieved using gas vapour, physical or chemical sterilant. The purpose : To achieve the Safe Preservation at Room Temperature of treated products 4  Methods of sterilization  Physical Sterilants:  Flaming, steam under pressure,  filtration, ultraviolet radiation and  ionizing radiation Requires prolonged exposure times  Chemical sterilants: and damages many instruments,  per acetic acid Not Currently recommended  glutaraldehyde  Gas Vapour sterilants:  ethylene oxide,  formaldehyde,  hydrogen peroxide vapour, plasma gas 5 Other type of Boiling is inefficient because only at maximum heating methods temperature of 100°C Vegetative organisms are killed But not the spores which remain Viable. Widely used, inexpensive, non-toxic, Reliable method of sterilization. 6  Chemical methods of sterilization. Gas Vapour sterilants: Ethylene oxide, Formaldehyde, Hydrogen peroxide vapour,  Plasma gas 7 Chemical methods of sterilization. Ethylene oxide gas  used to sterilize sensitive items such as catheters and multi-lumen tubing products  Plastic packaging or plastic containers.  Equipment with integrated-electronics  Wound care dressings Gas Vapor sterilants: Plasma gas sterilization Effective in destroying the components of microorganisms, such as enzymes, nucleic acids, and DNA. Advantages: Efficient sterilizing method None toxic bye products 8  Chemical sterilization In an automated machine bronchoscopes To sterilize medical, surgical, and dental instruments (e.g., endoscopes, bronchoscopes). Chemical sterilization 2 Aldehydes (glutaraldehyde) It is used to sterilize surgical instruments. 9  Disinfection  Disinfectants : are substances that are applied to non-living objects to destroy microorganisms that are living on the objects.  Disinfection does not necessarily kill all microorganisms, especially resistant bacterial spores  It is less effective than sterilisation  which is an extreme physical and/or chemical process that kills all types of life What is the Purpose of disinfection ?  To make a surface free of any disease-causing microorganisms that are normally of health-hazard  Microbes are destroyed by disinfection but the more resilient organisms can survive. 10  Disinfectant levels They can be grouped into three:  high level,  used on equipment that can not withstand sterilisation; e.g. Surgical equipment with plastic  intermediate level disinfectants (alcohols)  used to clean surfaces or instruments on which contamination with spores are unlikely.  low level disinfectants (quaternary ammonium compounds),  used to treat non critical devices such as blood pressure kits, stethoscopes Methods of Disinfection  Heat; moist heat 750C to 1000C  Liquid: hydrogen peroxide, Formaldehyde, alcohol, chlorine dioxide 11  High-level disinfectants  Used for items that cannot withstand sterilization procedures  (e.g. certain types of endoscopes and surgical instruments with plastic components).  Examples:  moist heat  and use of  chemicals such as glutaraldehyde, hydrogen peroxide, Peracetic acid and chlorine compounds. 12 Chlorine compounds: Chlorine is very strong oxidizing agent Aqueous solutions of chlorine are rapid bactericidal. However, spore- forming organisms more resistant. 13  Intermediate-level disinfectants  Used to clean surfaces or instruments where  contamination with bacterial spores and other resistant organisms is unlikely.  It is used for semi-critical instruments  e.g. flexible fibre optic endoscopes, laryngoscopes, vaginal specula, anaesthesia breathing circuits,  and other items.  Examples: alcohols, iodophor compounds, phenolic compounds 14  Alcohols  Most commonly used are:  ethanol and isopropanol.  They are rapidly bactericidal against vegetative bacteria, mycobacteria, some fungi, and lipid-containing viruses.  Do NOT act against  bacterial spores and  Have poor activity against some fungi and  Non–lipid-containing viruses.  Uses: for skin surfaces and, to disinfect items such as thermometers 15  Iodine (tincture of iodine) Is a highly reactive element that precipitates proteins and oxidizes essential enzymes.  It is microbicidal against virtually all organisms, including spore-forming bacteria and mycobacteria. 16 Iodophor compounds (iodo,“iodine”;phor,“c arrier”): Povidone iodine (iodine complexed with polyvinylpyrrolidone 17  Phenolic compounds e.g. phenol carbolic acid  Phenolic compounds are active against  the Mycobacteria because the  cell wall of these organisms  has a very high concentration of lipids. Phenol is not sporicidal at room temperature, but is sporicidal at temperatures approaching 100°C, and it has poor activity against non–lipid-containing viruses. 18  Low-level disinfectants  Used to treat non-critical instruments and devices,  such as  blood pressure cuffs,  electro cardiogram electrodes,  and stethoscopes.  Examples: quaternary ammonium compounds Are bacteriostatic at low concentrations and bactericidal at high concentrations. However, organisms such as Pseudomonas, Mycobacterium, many viruses, bacterial spores and the fungus Trichophyton are resistant to these compounds. Quaternary Ammonium Compounds 19  Antiseptics  They are antimicrobial substances that are applied to; living tissue to reduce possibility of infection or sepsis.  They are used to reduce the number of microbes on skin surfaces  No sporicidal action is implied. Antiseptic agents  They are selected for their safety and efficacy.  Examples:  Alcohol, 70% - 90% [e.g.  Iodophor (Betadine)  Chlorhexidine  Triclosan 20  Alcohol Advantages include the following: Excellent activity against almost all groups of organisms except spores. they are Non-toxic. Disadvantages: Dryness to skin surface [remove lipids] Have no residual activity Inactivated by organic matter (clean the skin before alcohol is applied. 21 Iodophors (Betadine) Advantages relatively stable Non toxic to tissues Activity is similar to that of alcohols. Disadvantages: Slightly more toxic to the skin than alcohol compared with other iodine solutions 22 Chlorhexidine Has broad antimicrobial activity. Has residual activity Kills organisms at a much slower rate than alcohol. Triclosan: active against bacteria but not against many other organisms It is a common antiseptic agent in deodorant soaps and some toothpaste products. 23 Thank you 24