University:
American Career College
Course:
NURS115 | Intermediate Medical
Academic year:

2020
Views:

267

Pages:

19
Author:

Jazmyn Acevedo

Definition Sterilization  Destruction or removal of all viable organisms  Physical, gas vapor, or chemical sterilants Disinfection  Killing, inhibition, or removal of pathogenic organisms • Bacterial spores and other relatively resistant organisms (e.g., mycobacteria, viruses, fungi) may remain viable.  Usually chemical, used for disinfection  Categorized as high level, intermediate level, and low level Definition Antisepsis Use of chemical agents on skin or other living tissue To inhibit or eliminate microbes; no sporicidal action is implied Germicide • Chemical agent capable of killing microbes; includes virucide, bactericide, sporicide, tuberculocide, and fungicide Selection of an Antimicrobial Procedure The ultimate choice depends on  Type of Microorganism  Numbers of Microorganisms Initially Present  Environmental Conditions  Potential Risk of Infection Heat  Moist heat  Degrades nucleic acids, denatures proteins, and disrupts membranes  Effective against all types of microorganisms  Dry heat sterilization  Oxidizes cell constituents and denatures proteins less  Effective, requiring higher temperatures and longer exposure times Moist Heat Methods  Denaturation of proteins, destruction of membranes and DNA  Steam under pressure; sterilization  Autoclave 15 psi /121oC to 134/ 15-20min  Steam must reach surface of item being sterilized  Item must not be heat or moisture sensitive Autoclaves  If water is heated under pressure, its boiling point is elevated, so temperatures above 100oC can be reached  Pressure: 15 lbs per square inch (psi)  15 – 20 minutes at 121oC  Prions are highly resistant and must be sterilized longer and at higher temperature (134oC for 18 min) 8 Boiling water  Destroys microorganisms by coagulating their proteins irreversibly  Boiling (100°C) for 10 minutes readily destroys most organisms and viruses Dry heat sterilization Hot Air Oven  Burns the cell constituents, oxidizing them to ashes or irreversibly denaturing proteins  Noncirculating air at temperatures of 160°C to 170°C for 2 to 3 hours  200°C for 1.5 hours of dry heat is the killing equivalent of 121°C for 15 minutes of moist heat Glass Petri dishes Glass pipets 10 Tyndallization  Intermittent sterilization for substances that cannot withstand autoclaving  Items exposed to steam for 30 – 60 minutes, incubated for 23-24 hours and then subjected to steam again  Repeat cycle for 3 days  Used for some canned foods and laboratory media  Disinfectant Pasteurization  Heat is applied to kill potential agents of infection  63°C - 66°C for 30 minutes (batch method)  71.6°C for 15 seconds (flash method)  Does not kill endospores or many nonpathogenic microbes Radiation Nonionizing radiation Ionizing radiation 13 Nonionizing radiation  Nonionizing radiation  Ultraviolet (UV) radiation  Limited to surface sterilization because UV radiation does not penetrate glass, dirt films, water, and other substances Ionizing radiation  Ionizing radiation  Gamma rays, X-rays, cathode rays  Penetrates deep into objects that has sufficient energy to cause electrons to leave their orbit, breaks DNA  Destroys bacterial endospores; not always effective against viruses  Used for sterilization and pasteurization of antibiotics, hormones, sutures, plastic disposable supplies, and food Gamma radiation from the radioisotope cobalt-60 is effective for controlling most microorganisms 15 Filtration  Physical removal of microbes by passing a gas or liquid through filter  Used to sterilize heat sensitive liquids and air in hospital isolation units and industrial clean rooms Filtering Liquid Nylon membrane with bacterial removal rating of 0.2 μm polycarbonate membrane with 0.4 μm pores Filtering air Surgical masks High-efficiency particulate air (HEPA) filters  Used in laminar flow biological safety cabinets