1 Disinfection and sterilisation Mongolia 2011 Prof Dr Walter Popp 1 Prof. Dr . Walter Popp Hospital Hygiene, University Clinics Essen, Germany Term Definition Reduction factor of germs Cleaning Remove dirt including microorganisms (no need to kill them) by mechanicla 10 - 100 means. Mostly wiping with water (and detergents). Sometimes vacuum or high- pressure water blaster. disinfection Reduction of number of pathogenic microorganisms so that they are not enough to cause an infection 1.000 – 100.000 2 to cause an infection. Sterilisation Killing all bacteria (including spores), mould/fungi, inactivation of all viruses. Every sterile product has to be sterile!
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Disinfection and sterilisation
Mongolia2011
Prof Dr Walter Popp
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Prof. Dr. Walter PoppHospital Hygiene, University Clinics Essen, Germany
Term Definition Reduction factor of germs
Cleaning Remove dirt including microorganisms (no need to kill them) by mechanicla
10 - 100
) ymeans.
Mostly wiping with water (and detergents).
Sometimes vacuum or high-pressure water blaster.
disinfection Reduction of number of pathogenic microorganisms so that they are not enough to cause an infection
1.000 – 100.000
2
to cause an infection.
Sterilisation Killing all bacteria (including spores), mould/fungi, inactivation of all viruses.
Every sterile product has to
be sterile!
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Sterility
Definition:Sterile means that a product is free of bacteria, their spores, mould/fungi, viruses must be inactivated, also prions.
But:But:Their is no 100-% safety.
Therefore:DIN EN 556 defines a grade of safety (SAL = Sterility Assurance Level) of a sterilisation process for medical devices.Normally SAL of 10-6.This means:A sterilisation process is accepted if there is only one unsterile product in 106 (= 1 Million) sterilised products.
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Sterility
Testing a new sterilisation process:It is impossible to test 106 products.Therefore testing with bacteria which are hard to sterilise, measuring physical parameters like temperature or pressure water qualityparameters like temperature or pressure, water quality…
Attention:A device has to be sterile at the site of use (patient!).This means the product has to be wrapped before sterilisation! And sterilisation is going on despite wrapping!Wrapping in case of autoclavation: Steam has to pass the wrapping in both ways but no bacteria!
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Sterilisation:
Physical:Autoclave
Saturated water steam121°C, 2 bar, 15-20 minutes134°C, 3 bar, 5 minutes
Control of parameters (online registration of temperature and pressure).p )
Thermologger.
Chemical:
Chemical indicator on charge.
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Biological:
Biological indicator (spores): e.g. spores of Geobacillus stearothermophilus
Every half year or 400 charges
Use 5: 4 in autoclave, 1 as positive control
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Some other chemical control system
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Sterilisation – other quality necessities
Staff must be trained:
Basic course.
Repeated training.
Documentation of training.
Validation of sterilisation (reprocessing of medical devices): yearly
Documentation:
Temperature, pressure …
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p , p
Unblock sterile products
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Storage of sterile products
Dry environment
Own room (sterile air) or cupboard (closed storage)
no shelfes (open storage)
Time frame for usage:
Open storage: within days
Own room or cupboard: 6 months
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Physical disinfection methods are better than chemical ones:Higher safety of disinfection!
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Burning of wound
Disinfection
Disinfection of surfaces:Bucket with water and disinfectionFloors (often only cleaning)Furniture (especially near to patient)
Disinfection of medical devices:Used instruments: cleaning – disinfection – sterilisationBest of all washer disinfectorsSecond choice: manual disinfection
Skin disinfectionOperation, take blood …Alcohol
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Alcohol
Hand disinfectionAlcohol
Mucous membranes disinfection
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Disinfectants for surfaces and manual disinfection of medical devices
Cold water, use dosing aid, gloves, protective goggles, do not mix with soap oder detergents!p g
Better use a dosing unit
Surfaces disinfection:
Wipe
Concentration and time
Time usually not to be waited for
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Instrument disinfection:
Different times and concentrations available
Keep the respective time
Spraying only if wiping is not possible:Combine with wiping!
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Chemical disinfectants and their usage
Viruses bacteria Bacteria spores
moulds hands skin surfaces
instruments
clothes
Alcohols (+) + - + + + (+) +
Formal- + + (+) + - - + + +Formaldehyde
( )
Glutaral-dehyde
+ + (+) + - - + +
Glyoxal + + - + - - + +
Quats + (+) - + - - + + +
PVP-iodine
+ + (+) + (+) + - - -
Chl i ( ) ( ) ( ) ( )
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Chlorine + + (+) + (+) (+) (+) +
Perace-tic acid
+ + + + (+) + +
phenol (+) + - + - - - - -
Oxidants
Reactive oxygen species:
Hydrogen peroxide, ozone, peracetic acid and related substances.
Hydrogen peroxide: no disinfectant – not enough active against bacteria and viruses.
Ozone: only water disinfection.
Peracetic acid: disinfectant, also partly effective against spores
Explosive, must be down concentrated, corrosive, concentration is di i i hi ith ti
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diminishing with time
Also new related substances available without toxic profile.
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Other problems with disinfectants
Protein mistake (looses effect after reaction with proteins):Aldehydes, peracetic acid, quats, chloramine
Soap mistake (looses effect after reaction with soap/detergents):Iodine, quats, phenole, chloramine
corrosive:Peracetic acid, chloramine
Effect on plastics:Al h l di l t ht l t ( l ti i d PVC)
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Alcohol may dissolve out phtalates (plasticized PVC)Alcohol may damage plexiglassPhenol and alcaline solvents may damage polyethylene, polypropylene, polyamide