The role of Disinfection/Sanitization/Sterilization in the

Laboratory Animal Facility

By Belinda Buehl

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Why is it important?

Integrity of the research project

Colony health

Employee health

Required by rules and regs from AALAS and “The Guide”

Reduces biohazards

What is the difference?

Disinfection: Reduction of the # of pathogenic microorganisms on an object to harmless levels.

Sanitization: Reduction of the # of microorganisms on a object to a level acceptable for public health standards.

Sterilization: Destruction of all organisms on an object.

-cidal: kills

-static: inhibits

Methods you might use

Autoclave

Gas sterilization

Chemical

Radiation

Other

Autoclave

Uses steam under pressureLength of time dependent on # of items sterilized, minimum is 15 min @ 250°F(121°C) at 15 psi Large and small models available depending on use

Positives and Negatives of Autoclaving

Positives

Inexpensive

Reliable

No use of toxic chemicals

Negatives

Can be corrosive

Many objects cannot withstand autoclaving

Use of high temperatures and pressure can be dangerous

Items must be wrapped in appropriate materials and the autoclave must not be overloaded or steam won’t penetrate objects

Gas Sterilization

Uses ETO (Ethylene oxide gas)

Kills all known viruses, bacteria, & fungi (even bacterial spores)

Positives and Negatives of ETO Gas Sterilization

Positives

Good for instruments that cannot be steam sterilized

Effective against bacterial spores

NegativesSpecial equipment is required

Gas is colorless, toxic, and very flammable

Materials to be sterilized must be dry, and well aerated once sterilization is done

Explosive!

Chemical Sterilization

Most commonly used for surgical instruments

Cidex (glutaraldehyde) is most common

Requires 3 hours or more of exposure time

Bactericidal, fungicidal, viricidal, and sporicidal

Can be used for other surfaces

Formalin/Formaldehyde

Often used to sterilize rooms

Used in a “bomb” form: formalin soln or crystals are heated & allowed to dissipate throughout the room

Toxic, carcinogenic, corrosive: i.e. DANGEROUS

Rooms must be free of any metal material or organic debris

Rooms must also be sealed completely and not entered for at least 24 hours.

Limited penetrability

Chemicals for disinfection

Phenols

Alcohols

Halides

Aldehydes

Phenols

1st used in clinical practice

Phenol itself is corrosive and toxic

Chlorhexidine is a phenol derivative common in the lab animal field

Can be used as a skin disinfectant

Alcohols

Methanol, ethanol, isopropanol

Works by dehydrating cells, coagulating proteins, and disrupting cell membranes

70% aqueous solution is more effective than full strength

Halides

Chlorine and Iodine

Powerful oxidising agents

Rapidly become inactive in the presence of organic material

Sodium hypochlorite (bleach) and Povidone iodine are common preparations

Aldehydes

Denature proteins

Glutaraldehyde and formaldehyde (also used for sterilization)

Become inactivated in the presence of organic matter

Methods of disinfection, etc used by the lab animal tech

All of the above mentioned could be a method used

There are many methods to prevent spread of disease such as:

Disinfecting foot baths

Dedicated mops, brooms, buckets to animal rooms

Following strict guidelines on how often rooms, cages, etc are to be cleaned

Wash hands often!!!!

Personal Protective Equipment

Very important to think about when using the methods described

Some forms of PPE would be heatproof mitts, masks, goggles, gloves, rubber boots, coveralls, face shields, respirators, and more

Guidelines

Always follow guidelines on the instruments or chemical containersKnow where the MSDS sheets are located (Material Safety Data Sheets)Never dilute chemicals more than required as they may not be as effectiveLikewise, don’t use a soln. that is too concentrated, it could be harmful to you and the animalsFollow the rules set forth by The Guide for the Care and Use of Laboratory Animals and by AALAS.Have SOP’s (Standard Operating Procedures) written up and located in binders for reference.If you have questions, ASK!!!!!!!

Where could you work as a Lab Animal Tech?

You’d be surprised!University campusesPharmaceutical companiesWildlife facilitiesGovernmental agencies (state and federal)Private corporationsPet food companiesAnd many more!!!

A little about me

BS in Wildlife Management and Conservation Biology

Associate Degree as a Veterinary Technician and Laboratory Animal Technician

Worked at the following facilities:Department of Agriculture, Trade, and Consumer Protection

Dane County Humane Society

DNR Bureau of Wildlife Management

National Wildlife Health Center

Deer-Grove Veterinary Clinic

MATC

Covance

UW Madison – Veterinary Medicine Teaching Hospital

Animals I have worked with as a Lab Animal Tech

Any Questions????