Asepsis and Sterilization Pradeep-Wednesday Talk Final1

7/27/2019 Asepsis and Sterilization Pradeep-Wednesday Talk Final1

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Asepsis, Sterilizationand Disinfection

Pradeep B Patil


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Sushruta 1500BCE


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Hippocrates (460-377 BC)

Separated medicine from

philosophy

Irrigated wounds with wineor boiled water

Foreshadowing ofAsepsis
http://www.urmc.rochester.edu/Sterile/glossary.htmlhttp://www.urmc.rochester.edu/Sterile/glossary.html


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Joseph Lister

chemical antiseptics tocontrol surgery relatedinfections

disinfect surgical equipmentand supplies

Microorganisms are simple forms of life commonly made up

of a single cell only seen with a microscope.


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Pasteur (1862)

Discovered bacterium

Developed Pasteurizationprocess


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Mikulicz-Radecki (1887)---face masks

Furbringer (1889)-----------hands-scrubbingHalsted (1890)---------------surgical-gloves


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Basic terms

Sterilization

Disinfection

Antisepsis

Bacteriostasis

Asepsis


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Microbial Control

Degerming: Removing microbes from a limited area

Sanitization: Lowering microbial counts on eating

utensils

Biocide/germicide: Kills microbes

Bacteriostasis: Inhibiting, not killing, microbes


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Effectiveness of Treatment

Depends on

Number of microbes

Environment (organic matter, temperature, biofilms)

Time of exposure

Microbial characteristics


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Actions

Alteration of membrane permeability

Damage to proteins

Damage to nucleic acids


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1. Medical asepsis

Wash hands

Sanitize & disinfect equipment

2. Use of PPE

Gloves, Mask, Gown

3. Deal with waste & disposal

OSHA --- deals with waste in facility

EPA --- deals with waste outside facility

4. Sterilize instruments

5. Spillage

Standard Precautions


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Handwashing


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Using alcohol based hand rub

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SPILLS

should be promptly cleaned up

clean up = * gloved employee

* paper towels

* infectious waste container after clean up :

disinfect area with bleach solution

household bleach = 5.25% sodium hypochlorite

bleach solution = 1:10 dilution


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Surgical Asepsis

Surgical Asepsis and Sterilization

Steam Sterilization (Autoclave)

Dry Heat Sterilization

Gas Sterilization

Chemical Sterilization


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1.Chemical agentsAlcohols,Chlorine, Formalin

Suitable for skin and instruments

2. Radiation

3. Dry Heat

Ultraviolet and Ionizing Radiation

Suitablefor sterile room and inoculation hood

Direct flaming: e.g. inoculating loop

Hot-air sterilization :160, 2h in hot air oven

4. Moist Heat12130min in autoclaveSuitable for medium and instruments

5. FiltrationRemoval of bacteria by filter medium

Used for heat sensitive materials and filtrated air


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Heat sterilizationhow it works?

Dry heat- protein oxidation

Moist heat- protein denaturation


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Wrapping for Sterilization Techniques involves sanitizing (washing & cleaning)

make sure things are in proper working order

these materials allow steam or chemical vapors to penetrate,

but do not allow airborne or surface contaminants to enter

muslin = cotton fabric----------------Shelf Life = 1 month

special paper ------------------------- Shelf Life = 1 month

special disposable envelopes ------ Shelf Life = 3 months

Technique for paper & muslin :

Diamond; Bottom; Right Side; Left Side ; Fold Up


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Flaming

Hot air oven

-170C for 1 hour

-140C for 3 hours

.

Dry Heat


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1. Pasteurization( below 100C)

Destroys pathogens without altering the

flavor of the food.

Low temperature (holding method): 63 , 30 min

High temperature (flash method) : 72 , 20sec

Moist Heat


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2. Boiling (at 100C)

-killing most vegetative forms of bacteria

-10 min or longer time

3. Autoclaving (above 100C)

-killing both vegetative organisms and endospores

-121-132 oC for 15 min or longer


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Moist Heat vs Dry Heat

Moist heat Dry heat

Penetrating potency higher lower

Temp. for protein clotting lower higher

Extra heat released yes no

from condensation

Sterilizing potency: Moist heatDry heat


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Why is moist heat more efficient than

dry heat ?

Conductivity. Moisture conducts the heat better than a

dry system.


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Sterilization processes

Batch sterilization

Continuous sterilization


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Filtration

Sterilize solutions that may be

damaged or denatured by high

temperatures or chemical

agents.

The pore size for filtering bacteria, yeasts, and

fungi is in the range of 0.22-0.45 m(filtration

membranes are most popular for this purpose).


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Air Sterilization

Very large volumes of sterile air is required in many aerobic

fermentation process.


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Methods for air sterilization

Radiation

High temperature

Electrostatic bacteria removal

Filtration


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WASTES1. Medical 2. Contaminated 3. Non-Medical

Medical ( Infectious) Waste 1. laboratory waste = chemicals, detergents, containers

2. pathology specimens = human tissue, blood, excrement, secretions

3. surgical specimens = human parts removed at surgery / autopsy 4. sharps = any device having rigid areas capable of cutting / piercing

5. liquid body waste = stool, excretions, secretions

6. contaminated waste things that have been used on body (dressings)

Non-Medical Waste - non-patient care waste - kitchen waste


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Aseptic Technique

1. Remove all jewelry (e.g., watches, rings, bracelets,

necklaces.


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2. Put on non-shedding coats, gowns, or coveralls (hospital

scrubs);

head and facial hair covers; face masks; and shoe covers.

Note that it is important to follow the sequence of items

indicated in this step.

Aseptic Technique


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Personnel protective equipment


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Keyboard and mouse with proper barrier protection


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3. Scrub hands and arms to the elbows thoroughly with

an antiseptic cleanser

(e.g., povidone-iodine or chlorhexidine gluconate).

Aseptic Technique


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4. Clean the laminar flow hood with isopropyl alcohol.

The alcohol must remain in contact with the surface for

30 seconds prior to compounding any sterile product.

Aseptic Technique


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5. Place only essential materials under the airflow hood

no paper, pens, or labels.

Remove the selected syringe(s) from its overwrap, attach aneedle, then discard the waste.

Aseptic Technique


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6. Scrub again and glove.

Aseptic Technique


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7. Swab or spray needle-penetration closures on vials,

injection ports, and other materials.

Aseptic Technique


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8. Prepare the sterile product by

withdrawing the medication from vials or ampules

introducing it into the IV container.

Aseptic Technique


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9. Complete a quality check of the product for

container integrity and leaks,

solution cloudiness,

particulates,

color of solution

proper preparation of product.

Aseptic Technique


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Figure 10.2


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HANDLING AND DISPOSAL OF

HAZARDOUS AGENTS Receipt and Storage of Hazardous Agents:

Hazardous drugs should be delivered directly to the

storage area, inventoried, and, if necessary, refrigerated.

Access to storage areas and work areas for hazardous

materials should be limited to specified trained personnel.

S# Waste class Type of container Colour


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S# Waste class Type of container Colour

1. Human anatomicalwaste, Animal wasteSolid (biomedicalwaste)

Plastic Yellow

2. Microbiology andBiotechnology waste

Plastic Red

3. Waste sharp Plastic bagpuncture proof

containers

Blue/WhiteTranslucent

4. Discarded medicinesand Cytotoxic waste

Chemical waste(solid)Incineration waste

Plastic bag Black


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Reporting Guidelines

National Notifiable Disease Surveillance System

Examples

HIV/AIDS Cholera

Rubella

Hepatitis Legionellosis Lyme disease

Mumps Smallpox

Tetanus Tuberculosis


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Sterilization of Surgical Instruments


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1906

1933

1947Steam Sterilization


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Early type of hot air sterilizer

Microwave Oven (1947)


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Advanced Sterilizer

Low temperature system for endoscopic devices

(1989)

Plasma sterilizing system

(1993)


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Steam Sterilization

Steam must contact items surface


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Filtration

HEPA removes

microbes >0.3 m

Membrane filtration

removes microbes

>0.22 m

Ph i l M th d f Mi bi l


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Physical Methods of Microbial

Control

Low temperature inhibits microbial growth

Refrigeration

Deep-freezing

Lyophilization

High pressure denatures proteins

Desiccation prevents metabolism

Osmotic pressure causes plasmolysis


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Figure 7.5

Radiation


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Radiation

Ionizing radiation (X rays, gamma rays, electron

beams)

Ionizes water to release OH

Damages DNA

Nonionizing radiation (UV, 260 nm)

Damages DNA

Microwaves kill by heat; not especially antimicrobial

Principles of Effective


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Principles of Effective

Disinfection

Concentration of disinfectant

Organic matter

pH

Time


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Biguanides

Chlorhexidine

Disrupt plasma membranes


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Halogens

Iodine

Tinctures: In aqueous alcohol

Iodophors: In organic molecules

Alter protein synthesis and membranes

Chlorine

Bleach: Hypochlorous acid (HOCl)

Chloramine: Chlorine + ammonia

Oxidizing agents


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Table 7.6

Alcohols

Ethanol, isopropanol

Denature proteins, dissolve lipids

Require water


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Heavy Metals

Ag, Hg, and Cu

Silver nitrate may be used to prevent

gonorrheal ophthalmia neonatorum

Silver sulfadiazine used as a topical cream onburns

Copper sulfate is an algicide

Oligodynamic action Denature proteins


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Chemical Food Preservatives

Organic acids

Inhibit metabolism

Sorbic acid, benzoic acid, and calcium propionate

Control molds and bacteria in foods andcosmetics

Nitrite prevents endospore germination

Antibiotics Nisin and natamycin prevent spoilage of cheese


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Aldehydes

Inactivate proteins by cross-linking with

functional groups (NH2,OH,COOH,

SH)

Use: Medical equipment

Glutaraldehyde, formaldehyde, and ortho-

phthalaldehyde


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Gaseous Sterilants

Denature proteins

Use: Heat-sensitive material

Ethylene oxide


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Infrared rays

Temperature =160

Time = 60-120 min


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Supercritical Fluids

CO2 with gaseous and liquid properties

Use: Medical implants


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Peroxygens

Oxidizing agents

Use: Contaminated surfaces

O3, H2O2, peracetic acid


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Figure 7.11

Microbial Characteristics


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Table 7.7

Endospores and Mycobacteria


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Disposal container for contaminated sharps

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Asepsis and Sterilization Pradeep-Wednesday Talk Final1