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PHC 6517: “Cleaning, Disinfection, & Sterilization, Part 1”

https://commons.wikimedia.org/wiki/File:Joint_Rea

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Part I Outline

• Definitions

• Levels of decontamination

• Levels of disinfection

https://en.wikipedia.org/wiki/Black%27s_Law_Dictionary

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Definitions

• Often interchanged

• Often used to apply inappropriately to inanimate objects or living tissue

• Alphabet soup of terms

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Hospital Environment

• Cleaning, disinfecting & sterilizing refer to inanimate objects, instruments

• Antisepsis refers to agents or practices affecting living tissue

• Asepsis refers to patient care practices

• Difference between what FDA & EPA regulate

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• Process of removing pathogenic (disease-producing) microorganisms from objects, thus rendering them safe to handle (think of it in levels)

• For bioterrorism, refers to process of removing agents from persons or environments

Decontamination

https://commons.wikimedia.org/wiki/File:Alabama_Guardsmen_perform_Chemi

cal_Training_with_Marine_Expeditionary_Unit_DVIDS202099.jpg

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Levels of Decontamination

• Cleaning

• Sanitizing

• Low-level disinfection

• Intermediate-level disinfection

• High-level disinfection

• Sterilization

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Cleaning

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Cleaning

• Physical removal of soil or organic material (blood, secretions) from objects

• using water & mechanical action

• with or without detergent, enzymatic products

• removes rather than kills microorganisms

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Hospital Cleaning

www.dallasdustbusters.com/index.php http://www.fotosearch.com/OJO227/pe0068563/

https://en.wikipedia.org/wiki/Terminal_cleaning

http://www.public-domain-image.com/free-

images/people/female-women/when-cleaning-windows-

personal-protective-equipment-should-be-worn

https://c1.staticflickr.com/7/6203/6103128464_c99324d98a_b.jpg

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Cleaning

• Single, most important stepin making medical device ready for reuse

• Without it, disinfection & sterilization are ineffective

• Debris on devices can interfere with function or lead to foreign-body/pyrogen reaction in patient if introduced into the body

https://en.wikipedia.org/wiki/Ultraviolet_germicidal_irradiation

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Types of Cleaning

• Manual

• Machine-driven

• Surface

• Object

• Instrument

http://www.mnn.com/sites/default/files/GreenCleaningHospital_mai

n.jpg

http://www.smsclean.com/images/photo_floor.jpg

http://www.freestockphotos.biz/stockphoto/16323

https://www.flickr.com/photos/tracywoolery/5438982335

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Wiping with Detergent-Dampened Cloth

• Can be used on mattresses, walkers, wheelchairs, intravenous fluid pumps, blood pressure cuffs (sphygmomanometers)

• Usually not contaminated with blood or body fluids

• If they are, require higher level of decontamination

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Wiping with Detergent-Dampened Cloth

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esfromrd/IN-TracerWCTop.jpg

https://en.wikipedia.org/wiki/Wheelchair

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g

http://www.public-domain-image.com/free-images/science/medical-science/measure-a-patients-blood-

pressure-a-sphygmomanometer/attachment/measure-a-patients-blood-pressure-a-sphygmomanometer

http://www.public-domain-image.com/free-images/science/medical-science/measure-a-patients-blood-

pressure-a-sphygmomanometer/attachment/measure-a-patients-blood-pressure-a-sphygmomanometer

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Manual Cleaning• Requires manipulation of device

• Possibility of glove & skin punctures

• Possibility of disease transmission

• Some devices cannot tolerate cleaning in automated machines or some hospitals don’t have them

https://commons.wikimedia.org/wiki/File:Surgical_instruments_15.jpg

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• Ultrasonic Cleaners

Cleaning with Machines

• Washer-Disinfectors

https://pixabay.com/en/ultrasonic-cleaner-devices-609651/ https://en.wikipedia.org/wiki/Miele

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Ultrasonic Cleaners

• Use energy from high frequency sound waves, to remove fine debris from surgical instruments

• Can use detergent & heat

• Can have rinse cycle

• Instruments must be free of gross debris

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Ultrasonic Cleaners

http://gotopac.files.wordpress.com/2010/10/mixed-units-4-21.jpg

https://commons.wikimedia.org/wiki/File:UZ%C4%8Disti%C4%8Dky.jpg

https://pixabay.com/en/ultrasonic-cleaner-devices-609651/

https://upload.wikimedia.org/wikipedia/commons/0/09/ATO

MO_Dental_premium_quality_ultrasonic_cleaner_GT-

1860QTS_with_accessories_for_dental_clinics.png

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Washer-Disinfectors

• Single or multi-chamber

• Fully automated (hands off)

• Devices are clean & at least intermediate level of disinfection

• Making them safe for handling but maybe not reuse

https://en.wikipedia.org/wiki/Miele

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Sanitation/Sanitizer• Process capable of reducing #’s of microbial

contaminants to relatively safe level (?)

• Does not require/ produce complete destruction of any particular microorganisms

• Agent that reduces # of bacterial contaminants to safe levels as judged by public health requirements

• Use: e.g., dishwashing machines

• No universal test method or standard

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Disinfection

• Falls between processes of physical cleaning & sterilization:

• the elimination of disease-producing organisms, but NOT spores

• from inanimate objects

• via wet pasteurization or liquid chemicals

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Disinfectant

A germicide that inactivates virtually all recognized pathogenic microorganismsbut not necessarily all microbial forms (e.g., spores) on inanimate objects

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3 Levels of DisinfectionHigh level: lethal process using a sterilant under less

than sterilizing conditions. The process kills all forms of microbial life except for large numbers of bacterial spores

Intermediate level: lethal process using an agent that kills viruses, mycobacteria, fungi & vegetative bacteria, but not spores

Low-level: kills vegetative forms of bacteria, some fungi & lipid viruses

Vegetative = active growth state

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Germicide

• An agent that destroys microorganisms, particularly pathogenic ones

• Agent that can be used on living tissue as well as on inanimate objects

https://pixabay.com/en/germ-bacteria-medical-virus-41366/

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Other “cides”

Cide- means to “kill”:

• Virucide• Fungicide• Bactericide• Sporicide• Tuberculocide

https://pixabay.com/static/uploads/photo/2012/04/11/16/50/germ-28874_960_720.png

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“-static”

• Means “to inhibit”

• Thus, bactericidal = kills & bacteriostatic = inhibits bacteria

“Static”- inhibits bacteria

“Cidal”-kills bacteria

https://pixabay.com/static/uploads/photo/2014/04/03/10/00/bacteria-309587_960_720.png

https://pixabay.com/static/uploads/photo/2012/04/11/16/50/germ-28874_960_720.png

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Bacteriostatic vs. Bactericidal

http://www.leeds.ac.uk/

http://tmedweb.tulane.edu/pharmwiki/doku.php/bacteriostatic_vs_bactericidal?do=

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Bacteriostatic Waterfor injections

https://upload.wikimedia.org/wikipedia/commons/d/d0/Heparin_Sodium_sample.jpg

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Sterilization

• Process of complete destruction of all forms of microbial life

• Bacteria, fungi, viruses & spores

• Accomplished by physical or chemical processes

• Absolute term

Gold

Standard

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Antiseptic

• Chemical germicide that prevents or arrests growth/action of organisms on living tissue either by inhibiting their activity or destroying them

• Should NOT be used on inanimate objects

• Registered & regulated as drugs (FDA)https://i.ytimg.com/vi/55Eldh9oj5c/hqdefault.jpg

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Reprocessing Medical Devices

• Evolution towards more complex reusable medical devices; advances in knowledge & technology

• Definition of reprocessing

• FDA’s 3 steps for healthcare facilities: – 1) point of use processing– 2) thorough cleaning, & – 3) disinfection or sterilization

• FDA’s 6 Criteria for Reprocessing Instructions

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Flexible Endoscopes• Outbreaks of gram (-) organisms from inadequately

cleaned scopes, including CRE

• Cleaning, disinfection/sterilization important issue (AERs)

• HICPACs 7 essential steps for endoscope reprocessing:– 1. pre-cleaning– 2. leak testing– 3. manual cleaning– 4. visual inspection– 5. disinfection or sterilization– 6. storage– 7. documentation

• Recommendations apply to all settings using/ reprocessing endoscopes

https://en.wikipedia.org/wiki/Endoscopy

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Figure 1. Decreasing order of resistance of

microorganisms to disinfection sterilization & the level of disinfection or sterilization.

Resistant Level

| Prions (Creutzfeldt-Jakob Disease) Prion reprocessing

| Bacterial spores (Bacillus atrophaeus) Sterilization

| Coccidia (Cryptosporidium)

| Mycobacteria (M. tuberculosis, M. terrae) High

| Nonlipid or small viruses (polio, coxsackie) Intermediate

| Fungi (Aspergillus, Candida)

| Vegetative bacteria (S. aureus, P. aeruginosa) Low

↓ Lipid or medium-sized viruses (HIV, herpes, HBV) Susceptible

Source: Required Reading #1, page 108

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Prions

• Creutzfeldt-Jakob Disease (CJD)

• Bovine spongiform encephalopathy (BSE) in cattle aka “Mad cow disease”

• Neurodegenerative diseases in sheep & goats

http://pathology.mc.duke.edu/neuropath/CNSlecture2/cjd.jpg

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Special Reprocessing for Prions

• Option 1- autoclave at 134°C for 18 minutes in a prevacuum sterilizer

• Option 2- autoclave at 132°C for 1 hour in a gravity displacement sterilizer

• Option 3- immerse in NaOH & transfer to autoclave

• Option 4- immersion, gravity displacement, cleaning, & sterilization

See details in slide transcript

https://upload.wikimedia.org/wikipedia/commons/3/3a/BOVINE_PRION_PROTEIN_1dx0_asym_r_500.jpg

bovine prion protein

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W.H.O. Guidelines

• WHO 2003 infection control guidelines for transmissible spongiform encephalopathies– Available at:

http://www.who.int/bloodproducts/publications/en/WHO_TSE_2003.pdf?ua=1

• Follow-up paper in 2006 entitled “WHO Guidelines on Tissue Infectivity Distribution in Transmissible Spongiform Encephalopathies”– Available at:

http://www.who.int/bloodproducts/TSEPUBLISHEDREPORT.pdf?ua=1

who.int

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Summary of Part I

• Definitions

• Levels of Decontamination

• Levels of Disinfection

• Reprocessing of medical devices

– endoscopes

– prions