Disinfection and Sterilization PDF

Dr. Ahd Mansour Ass. Prof. of Microbiology & Immunology Twitter. X.: @Dr.AhdMansour1 Student Learning Outcomes ❑ Define disinfection and sterilization. ❑ Explain the principles of sterilization, disinfection, and aseptic techniques ❑ Describe the differences between various...

Dr. Ahd Mansour Ass. Prof. of Microbiology & Immunology Twitter. X.: @Dr.AhdMansour1 Student Learning Outcomes ❑ Define disinfection and sterilization. ❑ Explain the principles of sterilization, disinfection, and aseptic techniques ❑ Describe the differences between various techniques in physical sterilization ❑ Differentiate between physical and chemical sterilizations  Three Levels of Infection Control Sanitization Disinfection Sterilization 1 2 3 The purpose of sanitization, disinfection and sterilization procedures is to The degree of prevent transmission of microbes to risk involved in patients (Infection control). their use.  Sanitization Cleaning and scrubbing instruments and equipment to remove contaminated materials and microorganisms Thorough cleaning is essential before high-level disinfection and sterilization because inorganic and organic materials that remain on the surfaces of instruments interfere with the effectiveness of these processes.  Disinfectants are Antiseptics kill used to kill germs on microorganisms on non-living surfaces living tissue and (inanimate objects). skin. Disinfection is not sporicidal ▪ A process that destroys or eliminates all forms of microbial life. ▪ It is sporicidal = eliminates bacterial spores. ▪ Only sterilization eliminates spores because of combining high heat and high pressure or using strong chemical compounds. A disinfectant that is used A disinfectant is suitable to reprocess reusable for general-purpose medical devices that may disinfection of building and come in contact with non- fitting surfaces, and intact skin. purposes not come in contact with nonintact skin.  o Antiseptics, o Disinfectants: 70% Ethanol, Iodine Benzalkonium chloride (Dettol), (betadine) Hypochlorite (Clorox) A disinfectant is a chemical substance or compound used to inactivate or destroy microorganisms on inert surfaces.  required contact time. No. of germs will be eliminated  When the chemical detergent is used at the same concentrations but for a shorter time of exposure Kill all microorganisms except large numbers of bacterial spores (e.g., a few spores that are usually nonresistant will be killed). Kill: Mycobacteria. Vegetative bacteria. Most viruses. Most fungi. not kill bacterial spores.  Kill: Some/most bacteria. some fungi. some viruses. No. of germs will be eliminated 1. Agents Modify cell membrane 2. Agents Modify Proteins 3. Agents Modify Nucleic Acids 1. Agents Disrupting Cell Membranes: Alcohols: ▪ Ethanol (70%). ▪ Fast acting, no staining. ▪ Skin antiseptic. ▪ Inanimate surfaces disinfectant 2. Agents modifying proteins: 1. Hypochlorites (Clorox): ▪ Disinfection of surfaces, blood spills. ▪ Chlorination of drinking water & swimming pools. 2. Tincture of Iodine & Iodophores: Skin antiseptics and staining. 2. Agents modifying proteins: 3. Aldehydes: ▪ Formaldehyde, (formalin), surface disinfectant. ▪ Glutaraldehyde (CIDEX) , is 10 times more effective than formaldehyde and is less toxic. ▪ CIDEX, is used in hospitals to sterilize respiratory therapy equipment, endoscopes, and hemodialysis equipment 3. Agents modifying nucleic acids: Crystal violet: Skin antiseptic  Sterilization Sterilization should be monitored periodically to test for contamination or failure of sterilization. It is achieved by indicators: Physical Chemical Biological  Sterilization monitored periodically by indicators: Physical  Sterilization monitored periodically by indicators: Chemical  Sterilization monitored periodically by indicators: Biological indicators (BIs), or spore tests, assess the killing Biological of known highly resistant, non-pathogenic bacterial spores directly.  Sterilization Biological 1. Weekly in oral healthcare facilities 2. Maintenance of the machine. 3. If there is an implant and the should be quarantined until the result of the spore test is known.  Sterilization Biological indicators Monitored periodically by indicators  Take Home Message Reusable vs disposable. Decontamination vs cleaning. Disinfection vs sterilization. Sterilization process. Sterilization monitoring indicators.  References Miller, C. H. (1993). Cleaning, sterilization and disinfection: basics of microbial killing for infection control. Journal of the American Dental Association (1939), 124(1), 48-56. Mohapatra, S. (2017). Sterilization and disinfection. In Essentials of neuroanesthesia (pp. 929-944). Academic Press. Schneider, P. M. (2013). New technologies and trends in sterilization and disinfection. American journal of infection control, 41(5), S81- S86. Sinha, D. K., Kumar, C., Gupta, A., Nayak, L., Subhash, S., & Kumari, R. (2020). Knowledge and practices about sterilization and disinfection. Journal of family medicine and primary care, 9(2), 793. Questions