Sterilization and Disinfection comm 2.pptx

Sterilization and Disinfection Prof. Dr. Pınar ÇIRAGİL,MD. Yeditepe University Medical Microbiology Department STERILIZATION ✔Killing or removal of all microorganisms (including highly resistant bacterial spores) ✔Use of physical procedures or chemical agents ✔Sterilization is a definite statement...

Sterilization and Disinfection Prof. Dr. Pınar ÇIRAGİL,MD. Yeditepe University Medical Microbiology Department STERILIZATION ✔Killing or removal of all microorganisms (including highly resistant bacterial spores) ✔Use of physical procedures or chemical agents ✔Sterilization is a definite statement ✔an object or environment are either sterile or not ✔less sterile, or very sterile are incorrect Destroy all microbial forms DISINFECTION pathogen ✔Use of physical procedures or chemical agents ✔To destroy most microbial forms ✔Bacterial spores, other relatively resistant organisms (e.g. mycobacteria, non-lipid viruses, fungi) may remain viable ✔For adequate disinfection pathogens must be killed Disinfectant Chemicals used in disinfection Inanimate environment tools Hygiene-Cleaning • Removal of foreign material from an object with the help of water, enzymatic solvents and detergents • Since the reproduction of microorganisms is reduced in a dry environment, it must be dried after each cleaning YOU CAN CLEAN WITHOUT STERILIZATION WITHOUT CLEANING YOU CAN NOT STERILIZE Antisepsis • Use of chemical agents on skin, mucose membranes or living tissue to inhibit or eliminate microbes Antiseptics live environment Pathogen Hand Hygiene -Antisepsis • Hand washing is one of the most important processes that prevent the transfer of microorganisms individuals • Water, soap and antiseptic • It is sufficient to soap the hands for 20-30 seconds in daily life between 5 May 8 9 Decontamiation • The process of removing pathogenic microorganisms from objects or living tissues by disinfection or sterilization or antisepsis Sterilization methods  Steam sterilization (heating in an autoclave)  Dry heat  Ionizing radiation  Gas sterilization  Filtration Sterilization Methods Heat Sterilization ✔ The most commonly used sterilization method ✔ With high temperature, the proteins of microorganisms are denatured ✔ Simple, cheap and fast results ✔ Does not create toxic waste for both employees and nature Sterilization Methods Heat Sterilization Temperature: As the temperature increases, the duration of sterilization process pH: Sterilization time is extended in neutral environment, shortened in acid and alkaline environments Humidity: The higher the humidity, the shorter the required temperature and duration of action -As the water content in the microorganism increases, protein coagulation becomes faster and sterilization becomes easier (Bacterial spores are more resistant to sterilization since water is less in them) Heat Sterilization A) Moist heat sterilization Sterilization with nonpressure steam Steam as a sterilizing agent Sterilization with hot water B) Dry heat sterilization Sterilization with pressure steam Boiling Tyndallisation Pasteur oven Flame and incineration Heat Sterilization A) Moist heat sterilization Steam as a sterilizing agent a) non-pressure steam Arnold boiler = Koch boiler 100°C at least 30 min Sterilization of heat susuceptible items Heat Sterilization A) Moist heat sterilization b) pressure steam (Autoclave) Sterilization in a steam-saturated environment, under pressure and at temperatures above 100°C The first autoclave developed by Charles Chamberland in 1879 Pressure cooker ?? pressure steam : Autoclave 3 most important parameters ; saturated steam, heat and time Hugo and Russell’s Pharmaceutical Microbiology 7th ed. 18 Autoclave Accidents An autoclave weighing 45 tons (diameter 4m, length 26m) jumped 4500m away 40 k g TNT equivalent explosion Heat Sterilization A) Moist heat sterilization Boiling - Disinfection; with boiling for 5-10 minutes at 100°C - Sterilization; by boiling for 30 minutes -Since tap water can be hard, distilled water should be preferred -Disinfection of materials such as forceps, scissors, scalpel in 5-10 minute at 100°C Heat Sterilization A) Moist heat sterilization Tyndallisation -Keeping liquid substances such as antigen, serum and sugar solutions that may deteriorate at high temperatures - for several days in a row at certain temperatures -Vaccines, protein substances such as blood or serum 60 minutes at 56-60°C Tyndallisation The process is repeated for 3 consecutive days and the materials are kept at room temperature for 1 night between each process 22 Heat Sterilization B) Dry heat sterilization -Dry heat is effective on microorganisms by creating oxidation -Since the moisture factor is eliminated, very high heat and longer time are required -is generally restricted to glassware and metal surgical instruments, thermostable powders Heat Sterilization B) Dry heat sterilization Pasteur Oven  They are double-walled ovens  Sterilization of glass, metalware, some powders, filter papers and oils This method cannot be used for sterilization of media and liquids Heat Sterilization B) Dry heat sterilization Pasteur Oven - 170o C - 1 hr - 160o C - 2 hrs Heat Sterilization B) Dry heat sterilization Flame In order to sterilize materials such as loops used in the microbiology laboratory, they must be heated in the flame until they turn red Heat Sterilization B) Dry heat sterilization Incineration (Burning) Dirty and unused materials (cotton, cloth) and animal cadavers can be incinerated Sterilization Methods Filtration According to filtration mechanisms; a) Filters that retain microorganisms by absorption (such as Berkfeld, Chamberland, Seitz) b) Filters that keep microorganisms mechanically (HEPA filters) Sterilization Methods Filtration Membrane filters Pore ​diameters; •0.45 µm for bacteria •3 µm for yeast cells •0.22 µm for viruses 29 Radiation sterilization UV rays (ultraviolet rays) What should be considered when using UV rays? - Use glasses or behind a glass, due to irritatation for eyes and skin -Pay attention to the duration of use -People should be taken out in the environment where it is going be used -After long-term use, the environment should be ventilated Disinfectants and antiseptics Chemical compounds -Have the ability to destroy or inhibit the growth of microorganisms -Disinfection is the process of removing microorganisms, from the surfaces of inanimate objects (Antisepsis & Live surfaces) -Not necessarily killing all microorganisms, but the pathogenic ones Chemical disinfectants High level disinfectants -All m.o. except bacterial spores in 20 min - Kills bacterial spores in 6-10 hours Intermediate level disinfectants - effective against tuberculosis bacillus and other microorganisms in about 10 min, except bacterial spores Low level disinfectants - can kill most vegetative bacteria, some fungi and some viruses in about 10 min. -Not effective against bacterial spores and TBbacilli Chemical disinfectants Different levels of action Hugo and Russell’s Pharmaceutical 34 35 Problems with the use of disinfectants Incompatibility with other substances -Some disinfectants become ineffective or do not get along when mixed with other cleaning agents -Quaternary ammonium compounds are incompatible with soaps and many normal detergents -Hypochlorites and some other halogen products are highly reactive, especially when mixed with acids - Absolutely no disinfectant should be used in combination with another, because both disinfection efficiency is reduced and can be toxic Problems with the use of disinfectants Preparation of dilutions -Concentrated disinfectants should be diluted in appropriate proportions before use -Disinfectant should not be less effective when diluted with liquids and in contact with organic substances -Hard water or sea water should not be used for dilution as much as possible, these waters are incompatible with some disinfectants Problems with the use of disinfectants Contact time -The contact time of the disinfectant with the surface should be sufficient (10-20 minutes) -Short contact provides bacteriostatic effect -High heat reduces contact time, while low heat does not always increase it Problems with the use of disinfectants Resistance - Especially if some disinfectants such as quaternary ammonium compounds are applied at frequent intervals, microorganisms can develop resistance -Using disinfectants for cleaning results in both resistance development and high cost Sterilization control methods Sterilization activities of autoclaves should be checked periodically and the records obtained should be kept for problems that may arise later Mechanical Control Biological Control Chemical Control Sterilization control methods 1. Mechanical Control -Time and temperature graphs recorded by the autoclave's printer -Inappropriate calibration of the indicators on the instrument may result in inaccurate results due to overuse and wear or metal fatigue Sterilization control methods 2. Chemical Control -Time, temperature and/or humidity sensitive tapes and strips use chemicals that change color at high temperature to control the temperature -These chemicals may be in a glass tube, or may be impregnated with an adhesive tape or a normal strip of paper Sterilization control methods 3. Biological Control -Strips and tubes containing bacterial spores -Biological indicators are the only control method that shows the true effectiveness of sterilization. - All microorganisms including spores in the indicator must be dead For steam autoclave; Bacillus stearothermophilus For dry heat; Bacillus subtilis For ionizing radiation; Bacillus pumilus