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34 Cards in this Set
- Front
- Back
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Define ASEPSIS
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The state of being free of microorganisms
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Define STERILIZATION
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Inactivation or elimination of ALL viable organism and their spores
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Define DISINFECTION
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Process of removing or killing MOST microorganisms on or in a material
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Define SANITIZATION
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A cleaning process which REDUCES pathogen levels to produce a healthy clean environment.
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What is a GERMICIDE?
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Substance that kills vegetative bacteria and some spores
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What is a DISINFECTANT?
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Substance used on non-living objects to render them non-infectious; kills vegetative bacteria, fungi, viruses but no spores
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What is an ANTISEPTIC?
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Substance used to prevent multiplication of microorganism when applied to living systems. An antiseptic is bacteriostatic in action but not necessarily bactericidal.
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What are the methods for Physical Sterilization/Disinfection?
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1. Incineration – for disposable wastes
2. Ultrasonification - Generally used to only clean materials, NOT used to sterilize, only cleans through cavitation 3. Filtration: < 0.22 µm pore. Removes microorganisms from liquids that would be destroyed by heat (e.g. enzymes, vaccines, antibiotics) 4. Radiation – used on materials that would be destroyed by heat (e.g. petri dishes, gloves, syringes) Ultraviolet = Thymine dimers – poor penetration Ionizing (Beta Rays, Gamma Rays, X-Rays) = breaks in DNA backbone 5. Hot air sterilization (160oC for 1-4 hours) used on materials that would be damaged by moist heat (e.g. gauzes, dressings, powders) 6. Steam and hot water Instrument sterilizer (hot water) that uses sodium carbonate and detergents. Harvey Vapor Sterilizer (alcohol plus formaldehyde under pressure) Arnold Sterilizer (Tyndallization) 7. Autoclave (15 lbs/sq inch pressure for 15-20 min at 121oC) Sterilizes with moisture, microorganisms are destroyed at a lower temperature than in dry heat. Method of choice when product can withstand such treatment since it is fast, least toxic, cheap, and can be performed on a large spectrum of instruments. Sterilizing indicators = Kilit Ampule - Spores of Bacillus stearothermophilus + fermentable sugar with pH indicator |
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How does Ethylene oxide sterilize/disinfect and what are the advantages and disadvantages of using it?
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Sterilizes via its action as a powerful alkylating agent
Low temperature sterilization = use for heat-labile materials and delicate instruments Requires hermetic oven for admission of gas + 20–50% humidity at 30–60oC Disadvantages: -Toxicity: eye and skin irritations, nausea, vomiting, respiratory tract disorder depression, intermittent high exposures = neurological and reproductive cancers - Explosive - No Liquid Sterilization |
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How does Formaldehyde (5%)
work and what is it most useful for? |
Broad-spectrum biocidal sterilizing activity
Surface and space decontamination. Mode of action = alkylation of carboxyl, hydroxyl and sulfhydryl groups on proteins and the ring nitrogen atoms of purine bases Drawbacks - reduction in efficacy at refrigeration temperature, pungent, irritating odor, and considered to be a carcinogen |
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How does Glutaraldehyde (2%)
work and what is it most useful for? |
Sterilizing agent against bacteria, spores and viruses
Often requires many hours of exposure. 10X more effective than formaldehyde and less toxic Toxic and causes skin sensitization. Cidex, a commercially prepared glutaraldehyde disinfectant is used routinely for cold surface sterilization of clinical instruments. |
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How do Alcohols (60% to 90%)
work and what are they most useful for? |
Mode of action - disruption of cellular membranes, solubilization of lipids, and denaturation of proteins by acting directly on S-H functional groups.
They evaporate rapidly, which makes extended contact times difficult to achieve unless the items are immersed. Used to clean instruments and wipe down areas but are Ineffective against spore-forming bacteria Alcohols are generally regarded as being non-corrosive Ethyl and isopropyl alcohols are most widely used |
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How do Halogens work and what are they most useful for?
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Principle ones used in disinfection or sterilization are iodine and chlorine
Uses – Chlorine = good as disinfectant if bleach is diluted to 1:10. Must be made fresh daily, Iodine = good as disinfectant and antiseptic Method of action – oxidizes microbial proteins |
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How do heavy metals sterilize/disinfect?
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protein sulfhydryl groups and disruption of enzyme functions
Mercury, Silver |
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How do Phenolics sterilize/disinfect?
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Disinfectants that act through MEMBRANE damage = good against enveloped viruses, rickettsiae, fungi and vegetative bacteria.
Retain more activity in the presence of organic material than other disinfectants. (e.g. Lysol, Pine-Sol) |
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How do Surface Active Agents (ionic detergents) sterilize/disinfect?
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Mode of action is through inactivation of energy producing enzymes, denaturation of essential cell proteins, and disruption of the cell membrane.
Not suitable for terminal disinfection since ineffective against viruses, spores and Mycobacterium tuberculosis |
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Which is the most accepted method for monitoring sterilization process?
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Biological
Directly assess killing of known highly resistant microorganisms ONCE PER WEEK MINIMUM |
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Sterilization can be accomplished by:
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- Steam sterilization (autoclaving 120oC for 20 min)
- Dry-heat sterilization (160oC for 1-2 hours) - Ethylene oxide sterilization - Ionizing radiation sterilization - Paraformaldehyde, aldehyde, and hydrogen peroxide with peracetic acid sterilants with appropriately long contact times |
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What is the Rule of Thumb for sterilization/disinfection?
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Autoclave if possible
Gas if material is liquid/moisture sensitive and heat sensitive (e.g. electronic equipment or paper) |
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Dry heat sterilization of dental instruments requires
A) 3 minutes at 270oF (132oC) B) 20 minutes at 250oF (121oC) C) 30 minutes at 320oF (160oC) D) 60 minutes at 340oF (171oC) E) 6 hours at 100oF (38oC) |
D) 60 minutes at 340oF (171oC)
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Which of the following represents the BEST way to verify heat sterilization
A) Using a chemical monitor B) Recording sterilizer pressure C) Recording duration of exposure D) Recording sterilizer pressure E) Testing with biological indicator |
E) Testing with biological indicator
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Which of the following disinfectants is effective against herpes simplex viruses but not rhinoviruses
A) Phenolics B) Iodophores C) Glutaraldehydes D) Sodium hypochlorite E) 70% isopropyl alcohol |
E) 70% isopropyl alcohol
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Which of the following is MOST resistant to sterilizing conditions
A) Oral Yeast B) Hepatitis B virus C) Bacterial endospores D) Mycobacterium tuberculosis E) Human Immunodeficiency Virus |
C) Bacterial endospores
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The spores of Bacillus anthracis are destroyed by:
A) Refridgerating (-7oC for 48 hours) B) Autoclaving (121oC for 20 minutes) C) Pasteurizing (61.7oC for 30 minutes) D) Immersing in boiling water (100oC for 10 minutes) E) Placing in a hot air oven (121oC for 20 minutes) The effectiveness of autoclaving is best |
B) Autoclaving (121oC for 20 minutes)
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The effectiveness of autoclaving is best determined by:
A) Culturing bacterial spores B) Culturing the water reservoir C) Thermocouples (temperature measuring device) D) Indicators that change color at elevated temperature |
A) Culturing bacterial spores
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Antiseptics differ from disinfectants in that antiseptics:
A) sterilize B) kill pathogens C) are bactericidal only D) are bacteriostatic only E) are applied to living tissue |
E) are applied to living tissue
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Sterilization of surgical instruments that are sensitive to heat can be accomplished by using:
A) phenol B) an autoclave C) ethyl alcohol D) ethylene oxide |
D) ethylene oxide
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In a dry heat oven, which of the following temperatures is sufficient for achieving sterilization in 1-2 hours
A) 81oC B) 100oC C) 121oC D) 160oC |
D) 160oC
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Personal protective equipment includes:
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Protective eye wear, chin-length shield, gloves, mask, gown
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True/False?
Non-sterile gloves can be used for non-surgical procedures |
True
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What is the purpose of Double gloving?
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to prevent cross-contamination of clean objects and reduced rates of total perforation
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Routine handwashing should last for how long?
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15 seconds
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Surgical Antisepsis handwashing should take how long?
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5 minutes
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The Chances of Getting Infected after skin puncture or broken skin contact with HBV are ____ while with HIV it is ____
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27-37% chance of getting infected with HBV
0.3 – 0.4% chance of getting infected with HIV |
