Disinfection and Sterilization
Sterilization
EVERYTHING IS DEAD! -use of a physical or chemical procedure to destroy all microorganisms including resistant bacterial spores. STERILE: free from all living microorganisms.
What classification is alcohol in terms of its ability to disinfect: high level, intermediate level, or low level?
Ethanol in concentrations of 70% and higher is considered an intermediate-level disinfectant and is considered broadly virucidal and tuberculocidal. The virucidal activity of isopropanol is limited primarily to lipid-containing viruses.
Does ethyl alcohol kill TB?
Ethanol is tuberculocidal. Adding ethanol to a disinfectant formula can shorten the required contact time for inactivation of the benchmark organism Mycobacterium tuberculosis .... but ..... may have no effect on contact time for other organisms.
2 Basic Types of Steam Sterilizers...Gravity Displacement
Majority of table-top units. How does it work? - Steam is admitted into chamber. - Pressure builds. - Unsaturated air is forced out through a vent.
How does it work? (Steam Sterilization)
Moist heat destroys m/o's by the irreversible coagulation and denaturation of enzymes and structural proteins
Surface Disinfection Process
PRODUCT: low to intermediate-level disinfectant. TECHNIQUE: 1) ''spray-wipe-spray'' 2) ''wipe-discard-wipe.'' First clean, then disinfect
Is it acceptable to use bleach as a precleaner for surfaces ... followed by ... glutaraldehyde for surface disinfection?
Some sodium hypochlorite (bleach) formulations are suitable surface disinfectants. It is important to ensure that the chemical will not damage the materials on the equipment and surfaces being disinfected. Because bleach is effective for removal of blood or other organic soils, it may be used as both a cleaner and disinfectant. WHAT??? Use a glutaraldehyde as a surface disinfectant??? ... NEVER ...
What is the best way to disinfect a dental chair?
The chair (except perhaps for control buttons and the headrest) is NOT considered high risk for cross contamination--->...does not require disinfection between patients UNLESS VISIBLY SOILED. ANSWER: ---> barrier to protect chair. TO CLEAN: follow chair mfg.'s recommendations. (Soap and water, rinse and dry) NOTE: Most disinfectants will stain and crack upholstery.
Steam Sterilization: Basic Principle
To expose each item to direct steam contact at the required temperature and pressure for the required time
Sterilization
Use of a physical or chemical procedure to destroy ALL microorganisms ... including resistant bacterial spores Sterile: free from all living microorganisms *Use of inadequately sterilized items represents a high risk of transmitting pathogens • Instruments/items that contact sterile body tissues or fluids are considered CRITICAL
What is the best way to disinfect utility gloves?
Utility gloves must be disinfected according to glove mfg's directions NOTE: To prevent contamination of bare hands remove heavy-duty gloves in a manner that does not require barehanded contact with outer surfaces of the gloves prior to decontamination
Some products received registration as a ''onestep'' disinfectant..
same product used to clean then REAPPLIED to disinfect. cleaning before disinfecting-->reduces bioburden -->helps assure that the disinfectant will work.
Dry Heat Sterilization
• Parameters: 60-120 minutes at 320F / 12 min at 375F) • Prolonged process (takes longer time) • Noncorrosive • Items are dry after cycle • High temps can damage some items • 2 types: - Static air type (aka: Oven-type): heating coils in bottom; heat rises inside through natural convection - Forced-air type (aka: Rapid Heat-Transfer): heated air is circulated throughout chamber; reduces time needed
Verification (Steam Sterilization)
• Physical monitors - Watch cycle indicators, dials and gauges, and lights • Process Monitors - External Monitors - Internal Monitors (Show ONLY that cycle parameters have been met) • Biological Monitors - Weekly - BI in load (test vial in load; compare w/control vial)
Ultrasonic Cleaner Unit
• Principle:cavitation • SafetyAdvantage
2 Basic Types of Steam Sterilizers... Prevacuum
• Require less time. • Can reach higher temps in shorter time. • How does it work? - Air in chamber is pumped out. - Creates a vacuum in chamber - Chamber is pressurized. • Faster and more positive steam penetration. • Test periodically for adequate vacuum action!
Chemical Vapor Sterilization
• moist heat from a chemical solution of primarily alcohol with a 0.23% formaldehyde in a closed pressurized chamber • Toxic potential; use in well-ventilated area • More expensive • Must predry instruments • Less corrosive to carbon-steel instruments • Less dulling of edges on sharp instruments
Steam Sterilization
• moist heat in the form of saturated steam under pressure. • Nontoxic. • Inexpensive. • Rapidly microbiocidal and sporicidal • Rapidly heats and penetrates cloths and wraps.
Tuberculocidal
---a chemical agent capable of inactivating Mycobacterium tuberculosis under laboratory test conditions specified by the EPA.
High-Level Disinfection
-->Traditionally defined as: ''complete elimination of all m/o's in or on instrument, except for a small number of bacterial spores'' NOTE: for semi-critical items/surfaces--> cleaning followed by high level disinfection is EXPECTED TO ELIMINATE ENOUGH PATHOGENS to precent transmission of infection.
Hospital Disinfectant
-A germicide for use of nonliving objects that is registered by the EPA as effective against ---Salmonella cholerasuis.. ---Staphlococcus aureus. ---Pseudomonas aeruginosa
Decontamination procedures
-Before/after pt. tmt. -Variety of procedures, based on: 1. Surface area and size of them. 2. Type of equipment or instruments. 3. Materials used in mfg. of the instruments/equipment. 4. Intended use of the item. -Three most common decontamination procedures used in dental setting---> sanitization, disinfection,sterilization.
One-Step Disinfectants
-Choose a disinfectants that is also classified as a CLEANER. -Eliminates need for a separate product to clean surface PRIOR TO disinfection
Non-Critical
-Come in contact with intact skin, but not mucous membranes -...sterility of items coming in contact with intact skin is ''not critical'' -EXAMPLES: hand mirror, bib, clips, pt safety glasses, BP cuffs. Method of decontamination-->SANITIZATION,DISINFECTION, BARRIERS
Technique..Wipe
-Disinfectant saturated wipe. -Wipe over surface til thoroughly wet to clean. -Discard wipe. -Wipe surface again to saturation to disinfect. -Allow surface to air-dry for REQUIRED CONTACT TIME. WIPE-DISCARD-WIPE.
Critical
-HIGH risk of infection if contaminated with any m/o. ---Penetrate mucous membranes. ---Used in/with invasive procedures. -Method of decontamination-->STERILIZATION
Immersion Sterilant(s)
-High level disinfectant. -Used for specified time period. -Instruments/items completely submerged-->complete microbial kill (aka:sterile)
Disinfection
-Inactivate all organisms, EXCEPT spores. -Kill most vegetative bacteria and viruses -Immediate and High level disinfectants---> protein denaturation, damage cell membrane, inhibit enzymes, alter nucleic material, MOST-->Combination -Disinfectants used in healthcare settings...MUST be registered with EPA -as hospital disinfectants AND have a tuberculocidal claim
Semi-Critical
-LOWER risk of infection if contaminated with m/o. ---Contact with mucous membranes or non intact skin ---Penetration NOT anticipated ---EXAMPLES: polisher head, air water syringe. -Method of decontamination-->STERILIZATION ---Minimally requires HIGH-LEVEL DISINFECTION using chemical disinfectants
Failure
-Most frequent cause of failure: *Operator Error •Improper loading of chamber •Overloading chamber
Comprehensive Infection Control
-Pre-procedure... BEFORE. -Direct procedure... DURING. -Post-procedure... AFTER.
Surface Disinfection TECHNIQUE
-Spray the surface to be cleaned with a cleaner or cleaner/disinfectant. -Wipe vigorously using paper towels. -Spray the surface again; cover entire surface-->allow disinfectant to remain undisturbed on the surface for the contact time indicated on label.
Surface Disinfection TECHNIQUE
-Wipe pre-moistened cleaner-disinfectant towelette VIGOROUSLY over the surface to be cleaned. -Discard towelette. -Wipe surface again with second towelette to thoroughly wet/saturate for required contact time. -Allow surface to air dry. *Check the label to be sure that the wipe is cleaner (some disinfectant wipes may require separate cleaner) *Carefully follow label instructions. Some wipes may be effective only on a limited surface area (approximately 3 sq. ft)
Glutaraldehyde
-a high-level disinfectant/sterilant (instrument-immersion disinfectant) -is HIGHLY IRRITATING to: skin, mucous membranes, and respiratory system *should NEVER be used as a surface disinfectant. -vapors--> associated with cases of occupational asthma. *Food and Drug Administration (FDA) requires that all glutaraldehyde labels warn that the product SHOULD NOT BE USED OUTSIDE A CLOSED CONTAINER!
Two Major types of disinfectants 2. General Use Disinfectants
-are the major source of products used in: households, swimming pools, and water purifiers
Chemical Disinfectant Criteria
-effective against a broad-spectrum of m/o's with short contact time -not inhibited by physical factors, as bioburden -not damage materials on repeated contact -have a residual effect on treated surfaces -be easy to use -be odorless -be economical
Low-level Disinfectant
-liquid chemical germicide registered with EPA as a hospital disinfectant. -Required by OSHA to also have a label claim for potency against HIV and HBV, if used for disinfecting clinical contact surfaces.
Intermediate-level Disinfectant
-liquid chemical germicide registered with EPA as a hospital disinfectant..and.. with a label claim of potency as TUBERCULOCIDAL
Sanitization
-lowest level of safety; doesn't target any specific m/o. -intended for general housekeeping surfaces. -Agents are: Low level cleaners or low level disinfectants.
Two Major types of disinfectants 1. Hospital Disinfectants
-most critical to infection control. -are used on medical and dental instruments, floors, walls, bed linens, toilet seats, and other surfaces.
Technique.. Spray
-nonaerosol. -spray to thoroughly wet surface. -Wipe wet surface to clean. -Spray again to saturation to disinfect. -Allow surface to air-dry for REQUIRED CONTACT TIME. SPRAY-WIPE-SPRAY.
Choosing and Using
-read the entire label!!! -use consistently with mfg. instructions. -know: *storage and shelf life, mixing and concentration necessary for proper use, effects of temp and time on effective use, requirements for PRECLEANING, intended for use as immersion sterilant, label warnings
Disinfection
-the destruction of pathogenic or other m/o's by physical or chemical means. -inactivate all organisms, EXCEPT spores. -Kill most vegetative bacteria and viruses.
Disinfection
-the destruction of pathogenic or other m/o's by physical or chemical means. -less lethal than sterilization...because it destroys the majority of recognized pathogenic microorganisms but NOT NECESSARILY ALL microbial forms...e.g. bacterial spores -Disinfection does NOT ensure the degree of safety associated with sterilization processes.
Surface Asepsis: Technique
-use fresh environmental barriers for each patient...OR... -clean and disinfect between each patient with a disinfectant spray using spray-wipe-spray..OR... -clean and disinfectant between each patient with a disinfectant wipe using wipe-discard-wipe (one wipe to clean followed by another wipe to disinfect)
3 Parameters Dry Heat Sterilization
1. Heat only 2.Pressure: None--> heat only 3. Temperature: 320 F/ 160 C 4. Time:120 minutes ; after correct temp reached
4 Parameters Steam Sterilization
1. Steam...standard steam (from water) 2. Pressure...15 psi 3. Temperature...250 F /121 C 4. Time... 15-30 minutes; 5 - 7 minutes AFTER correct temp and pressure reached
4 Parameters Chemical Vapor Sterilization
1.Heated chemical under pressure: saturated chemicals ''steam'' 2.Pressure: 20-40 psi 3. Temperature: 270 F / 132 C 4. Time: Minimum 20 minutes ; after correct temp and pressure reached
Disinfectant
A chemical agent used on inanimate objects/environmental surfaces...e.g.,floors,walls, or sinks --->to destroy virtually all recognized pathogenic microorganisms, but not necessarily all microbial forms (bacterial endospores)
What is the appropriate technique for disinfecting impressions?
A: Different materials require different handling techniques. Always consult the impression material manufacturer or the instructions for use on compatible disinfectants. 1. Rinse debris ... and ... drain 2. Spray hydrocolloid and polyether impression materials to saturate a. Place in a plastic bag or sealed container for the required contact time. 3. Immerse more stable silicone (vinyl polysiloxane) or rubber-based impression completely for disinfectant's required contact time a. usually 3-10 minutes
Q:Why do you have to spray a surface a second time with a disinfectant?
A: Many were registered with the EPA based on tests that first cleaned the surface...and then added the disinfectant to disinfect the surface. *The labels of those products will state ''Preclean the surface THEN disinfect by applying the product..'' or similar words.
Steam Sterilization Advantages
ADVANTAGES *Time efficient. *Good penetration, *Packaging: Paper, Plastic peel pouches, Cloth,Nonwoven Wrap, Wrapped perforated cassettes,
If soap is added to ethyl alcohol, will it become a more effective disinfectant?
Adding soap to alcohol may improve its usefulness as a cleaner but will not increase its germicidal efficacy.
Is ethyl alcohol a sufficient disinfectant for dental office surfaces such as countertops, cupboards?
Because alcohols are poor cleaners and evaporate rapidly, they may not be the best choice for use on environmental surfaces.
Barrier Wrap
COVER ANYTHING THAT CAN BE REASONABLY COVERED! • Bracket table and handpiece/dental unit control switches* • Handpiece and evacuator connectors and hoses* • Ultrasonic scaler connector and hose* • Air/water syringe handle and hose* • X-ray handle, PID, controls* and view box • Supply containers and bottles • Shade guides
Which decontamination process to use?
Choice based on: 1. degree of risk of infection involved (in use of the item/equipment/surface) 2. Spaulding Classification:Patient care items and environmental surfaces
Environmental surface disinfectants supplied as:
Concentrates,premixed solutions,sprays,foams, impregnated wipes, tablets.
Pump-sprays
Considered the best vehicle for delivering cleaning/disinfecting agents to contaminated surfaces.. -concentrates liquid on the surface (rather than aerosolizing it)--> allows chemical to penetrate into crevices. -spray bottles- less potential inactivation/absorption by: gauze, paper, or sponge applications
I read recently that placing disinfectant in a container with 4X4 gauze for use on dental equipment is not recommended. Can you explain why this should not be done?
Cotton fibers contained in gauze may shorten the effectiveness of some disinfecting agents when stored in containers together. Germicides, especially iodophors or chlorines, may be inactivated or absorbed by the gauze. As such, disinfectants should not be stored in containers with gauze. If used to apply disinfectant to surfaces, gauze should be saturated with the disinfecting agent at the time of use. Although this is an acceptable option, disposable paper towels typically are a more economical alternative.
Spaulding Classification
Critical, Semi-Critical, and Non-Critical
Steam Sterilization Disadvantages
DISADVANTAGES • Items may be wet after processing • Use of hard water may leave deposits • Nonstainless steel items may corrode
3 procedures
Decontamination procedure, Disinfection procedure, and Sterilization procedures.
What is the proper way to disinfect an environmental surface?
Disinfection consists of three steps: 1. Donning utility gloves, and all other PPE(mask, protective eyewear, and protective clothing) to guard against CHEMICAL EXPOSURE during cleaning and disinfection. 2. Cleaning the surfaces with a cleaning agent by vigorously wiping the contaminated surfaces with paper towels. 3. Disinfecting the pre cleaned surface by applying the disinfectant over the entire pre cleaned surface. Allow the surface to remain moist for the contact time recommended by manufacturer. Surface is still wet when patient treatment is to begin---> wipe dry with clean toweling. If surface will contact patient's skin-->rinse the residual disinfectant with water. Agreed-->using a single product formulated to both clean and disinfect environmental surfaces IMPROVES CLINIC TURN-AROUND TIME and REDUCES COST.
