Disinfection

8. Glutaraldehyde Glutaraldehyde is capable of effectiving sterilization—at room temperature, even against endospores , and even in the presence of organics, but achieving sterilization requries many hours of exposure … and it is nasty stuff to work with! www.freelivedoctor.com

10. Physical Antimicrobials www.freelivedoctor.com Agent Mechanisms of Action Comments Moist Heat, boiling Denatures proteins Kills vegetative bacterial cells and viruses Endospores survive Moist Heat, Autoclaving Denatures proteins 121°C at 15 p.s.i. for 30 min k ills everything Moist Heat, Pasteurization Denatures proteins Kills pathogens in food products Dry Heat, Flaming Incineration of contaminants Used for inoculating loop Dry Heat, Hot air oven Oxidation & Denatures proteins 170°C for 2 hours ; Used for glassware & instrument sterilization Filtration Separation of bacteria from liquid (HEPA: from air) Used for heat sensitive liquids Cold, Lyophilization (also desiccation) Desiccation and low temperature Used for food & drug preservation; Does not necessarily kill so used for Long-term storage of bacterial cultures Cold, Refrigeration Decreased chemical reaction rate Bacteriostatic Osmotic Pressure, Addition of salt or sugar Plasmolysis of contaminants Used in food preservation (less effective against fungi) Radiation, UV DNA damage (thymine dimers) Limited penetration Radiation, X-rays DNA damage Used for sterilizing medical supplies Strong vis. Light Line-drying laundry

15. Disk Diffusion Method www.freelivedoctor.com Hypochlorous acid Phenol Lysol Nisin Escherichia coli

16. Hands Spread Disease www.freelivedoctor.com

17. Link to Next Presentation www.freelivedoctor.com

18. Acknowledgements http://www.sw.vccs.edu/rth/RTH_132/decont.ppt http://www.nt.gov.au/powerwater/html/pdf/tennant_creek_chlorination.ppt http://www.bugcruncher.com/ws/docs/lekcii/D&S_INQUAL_eng.ppt (nice overview of specific antimicrobials) http://www.delmarhealthcare.com/olcs/white/ppts/chapter%2021.ppt (nice overview of microbilogy in nursing) http://www.countyofkings.com/health/ehs/forms/FDHNDLR.ppt http://bioeng.ttu.edu.tw/~chunyi/microbes/Chapter7.ppt http://microbiology.okstate.edu/courses/micro2124/babus/Chpt7_files/chapter7.ppt www.freelivedoctor.com

19. Chemical Antimicrobials * Type of Disinfectant: H = High level; I = Intermediate level; L = Low level www.freelivedoctor.com