PROF. Dr. ABDULRAHMAN ALQURASHIMSc. PhD (UK)

Professor & Consultant of M. MicrobiologyDean of Community College-Najran University

Kingdom of Saudi Arabia

STERILIZATION AND DISINFECTION IN HEALTH FACILITIES

Discussion points

• STERILIZATION & DISINFECTION• STERILIZABLE AND DISINFECTABLE CATEGORIES • HEALTH FACILITY AIR DISINFECTION• INSTRUMENTS’ STERILIZATION TECHNIQUES• CHEMICAL & BIOLOGICAL INDICATORS• PRE-STERILIZATION CLEANING OF INSTRUMENTS• CONCLUSIONS

• Sterilization refers to any process thateliminates, removes, kills, or deactivates allforms of microorganisms (such as fungi,bacteria, viruses, spore forms, prions andunicellular eukaryotic organisms).

STERILIZATION

DISINFECTION

• Is the process of killing or inactivating of most pathogenic microorganisms and cysts.

STERELIZABLE AND DISINFECTABLE OBJECTS

1) Healthcare workers-HCW (Doctors, Nurses etc.)

2) Patients’ site of procedure3) Instruments4) Rooms / Premises5) Disposal of Medical Waste

Magnified microbes on skin surface

HAND DISINFECTION-BETWEEN PATIENT CONTACTS

1. Soap / Detergent - Water Cleaning2. Iodophores Scrubs3. Alcohol gel (Newer method)§ Effective in eliminating microorganism§ Well tolerated - No irritation / No dermatitis§ Time saving & more effective compared with soap & water.§ Better staff compliance.

Available as alcohol gel dispensers• Use soap & water after every 10-12 uses of gel or if hands

become visibly contaminated with patients blood or body fluids.

• Alcohols: Disinfection of skin beforevenipuncture (70% ethanol).

• Detergents: Benzalkonium chloride usedfor skin antisepsis.

• Iodine compounds (Povidone iodine,Lugol's iodine and 2% iodine in ethanol) -skin antisepsis.

• Hydrogen peroxide - skin & woundantisepsis.

DISINFECTION OF PATIENT’S SKIN BEFORE PROCEDURE

• Air dilution (with natural clean air or filtered air).• Filtration (filtering clinics and rooms air with special filters).• UVGI: using ultraviolet lamps to inactivate pathogens

DNA/RNA. • Photocatalytic oxidation (PCO): where a chemical compound

is oxidized to simpler radicals using a strong reduction agent Tetanium dioxide (TiO2), tungsten trioxide (WO3), Zinc sulfide (ZnS) etc. in the presence of a light source (Fluorescent or UV light).

• Chlorin disinfection (Floors & surfaces with chlorine like Chlorax).

• Essential oils: essential oils’ antimicrobial effect is enhanced in air environment rather than when in solution media (lavender, rosemary, peppermint, chamomile, etc.).

HEALTH FACILITY AIR DISINFECTION

Microbes in room air

1. STEAM (AUTOCLAVE)

Used for: Wrapped, unwrapped materials and liquids.

Cycle times: 40 min @ 121oC

20 min @ 132oC

Newer Automatic Autoclaves:• Load the chamber - set it - forget it - doors

opens automatically.

• No worry being chained to the sterilizer.

INSTRUMENTS’ STERILIZATION METHODS

• Runs like a steam unit.

• Instead of distilled water utilizes a chemical solution (alcohol / formaldehyde).

Cycle time: 20 min @ 132oC

Flash cycle: 7 min @ 132oC (for a singleinstrument)

Advantages:• No time needed for drying

• Do not dull, rust or corrode instruments.

2. CHEMICAL VAPOR

3. DRY HEAT (Hot Air Ovens)

a) Convection dry heat units 160oC for 1-2 hr.b) Rapid heat transfer units - 375oF.

Cycle 1: Unwrapped - 5 minCycle 2: Handpieces & drills - 8 minCycle 3: Packaged instruments - 12 min.

4. ETHYLENE OXIDE (EO) MODIFICATIONS

a) Hydrochlorofluorocarbons / EO mixture.b) EO + 10% CO2 Mixture (non-explosive).c) 100% EO

- Faster- High speed cycles- Sharp instruments - sterilized &

ready to use in 30-60 min.- Most endoscopes in 60-90 min

5. ETHYLENE OXIDE ALTERNATIVESa) Peracetic Acid• Is highly toxic in normal state• In special formulation - high degree of

material compatibility. (less damaging to instruments than steam & EO)

• Non-toxic to environment, patient and worker.

• Mainly used for sterilization of rigid & flexible endoscopes.

6. EO ALTERNATIVES

b) Gas Plasma• Newer, faster, low temperature

sterilization.• Uses vapor peroxide• High instrument compatibility - fiberoptic

cords, batteries, endoscopes.

7. EO ALTERNATIVES

c) Ozone• Compact, easy and cost effective• Safe (no toxic chemicals, no harmful

emissions)• Only required - Oxygen, electricity &

water.• Oxygen - ozone - sterilization - oxygen• Automated - printed report confirms

sterilization.

8. The Self-cleaning Unit for the Decontamination of Small instruments (SUDS) [New device].

The machine utilizes Sporicidin® disinfectant solution.

9. GLUTERALDEHYDE DISINFECTANTS

• Used to achieve high-level disinfection for semicritical instruments.

• Available gluteraldehyde solution (2% - 2.4%)

a) 14-day solution without surfactants - can be used for endoscopes.

b) 28-day solution with surfactant - not used for endoscopes.

Soak time: 20 min at room temperature45-90 min for high-level disinfection

EQUIPMENT REQUIRING HIGH-LEVEL DISINFECTION

• Equipment that might be in contact with mucous membranes of natural orifices.

• e.g: § Face masks§ Laryngoscope pobes and blades§ Endotrachial and Endobronchial tubes§ Rectal probes§ Vaginal probes

• Equipment that touches only intact skin-should be cleaned with a disinfectant at theend of day and when visibly contaminated.e.g.§ Non-invasive blood pressure cuffs & tubing§ Stethoscopes§ ECG cables§ Head tapes§ Skin temperature sensors

EQUIPMENT REQUIRING CLEANING

DENTAL ASEPSIS AND STERILIZATION• Take into consideration that the patientmight has an infectious disease.

• Medical history & examination alone are notsufficient to identify patients infected bloodborne diseases (e.g. HIV).

• Blood, saliva and gingival fluid of dentalpatients are sources of infection that can notbe ignored.

DENTAL ASEPSIS AND STERILIZATION (CONT’D)

• Areas difficult to clean & disinfect (headrests, lighthandles etc) must be protected with barriers (plasticaluminum foil etc.).

• Before seating the patient: the potentiallycontaminable equipment and surfaces must becleaned and disinfected with a detergent.

• Patient chair, dental unit, hoses & attachments mustbe disinfected several times and dried with towels.

• All hand pieces and instruments used to manipulate and remove oral tissues must be heat sterilized between each cycle.

A. Precleaning:§ Essential to adequate sterilization.§ Use ultrasonic cleaner or washer / disinfector.§ Wear heavy-duty rubber gloves.§ Wear protective eyewear.

DENTAL ASEPSIS AND STERILIZATION (CONT’D)

DENTAL ASEPSIS AND STERILIZATION (CONT’D)

B. Sterilization process§ Flash - sterilized: Placed in autoclave unwrapped in

a single layer.

C. Heat-sensitive Instruments§ Place in an intermediate or high-level disinfectant

(gluteraldehyde) for approx 20 min.§ Remove the items with a clean pair of forceps

WASTE DISPOSAL

• Disposable of items contaminated with blood or saliva.§ Place in a Biohazard Box - seal the box for

disposal.

• Other contaminated waste§ Place in a chairside bag§ Seal the bag and dispose in a garbage

container

STERILITY QUALITY ASSURANCE

• Proper sterilization of instruments & materials is a critical aspect of infection control.

• Tools:-§ Mechanical / Electronic controls§ Chemical Indicators§ Biological Indicators (spore tests).

MECHANICAL / ELECTRONIC CONTROLS

• Easiest to use and interpret.• Provide earliest indication of unsatisfactory

conditions.• New sterilization systems have adjustable

alarms that alert the user to any changes in the system.

CHEMICAL INDICATORS (CI)Class I - Process Indicators (tapes or labels) for

external use. Class II - Bowie-Dick Indicators - Check Steam

Vacuum (Placed inside the material).Class III - Temperature-specific Indicators.Class IV - Multiparameter Indicators - more

accurate.- Check all parameters needed for

sterilization.Class V - Integrating Indicators.

• High level of sterility check.• Uses spores of highly resistant spores

(Bacillus stearothermophilicus, Bacillus sublitis)

Available as:-§ Spore strips§ Self - contained vials§ Sealed ampoules§ Spore suspension

BIOLOGICAL INDICATORS (BI)

INSTRUMENTS ’ PRE-STERILIZATION CLEANING

The most important steps before instrument sterilization is:• Removal of adherent visible soil, blood, proteins, fats

etc. from the surfaces, bumps, hinges and lumen of instruments with brushing in lukewarm water.

• Soak instruments in detergent- wash and brush several times - rinse several times with distil water - dry.

Cleaning Methods

• Mannal• Ultrasonic• Automatic• Washer - Disinfectors• Washer - Sterilizers

• Sterilization and disinfection for all the facets of any clinical facility is of paramount importance to assure and grantee the safety of workers, patients and working environment.

• Complying to regular sterilization of working environment, instruments, and devices guarantees safety at time of use.

• Absolute caution should be exercised when sterilizing with steam sterilization to avoid damage of heat sensitive devices.

• Sterilization gases (EO, formaldehyde) are toxic and accused of causing cancer.

• Research to develop new efficient, cost-effective and easy sterilization methods must continue.

CONOLUSIONS

MANY THANKS