Lesson 1.3 - Control of Microorganisms

Factors Influencing Chemical Agents

- Nature of disinfectant - Concentration of the disinfectant - Nature of the material to be disinfected - Number of microorganisms present - Type of microorganism present - Length of exposure to disinfectant - Temperature of the disinfectant during exposure - Disinfectant's pH during exposure

Sporicides

Agents that kill bacterial and mold spores, can also be used during the process of terminal disinfection of embalming instruments and equipment.

Disinfection

Destruction of pathogenic agents by chemical or physical means by applying the disinfectant to an inanimate object. Offers less control of the growth of microorganisms. Process does not inactivate microbial endospores; however, it does kill most vegetative microorganisms.

Alcohols

Ethyl Alcohol and Isopropyl Alcohol, are used to control microbial growth. Widely used disinfectants that control microbial growth be denaturing proteins and by dissolving lipids in the cell membrane of microorganisms. Most effective in aqueous solution because proteins are not soluble in high concentrations of alcohol.

Phenolic Compounds

Include phenol (carbolic acid), cresols (lysol), and hexachlorophene. Control microbial growth by denaturing proteins and disrupting cell membranes.

Germicides

Kill a variety of different types of microorganisms, but not necessarily their spores.

Bactericides

Kill bacteria but not necessarily their spores.

Insecticides

Kill insects

Larvicides

Kill larvae, which are wormlike forms of newly hatched insects

Viricides

Kill viruses

Antisepsis

Process by which microbial growth is inhibited on living tissue to prevent infection. Applied to living tissue.

Cremation is which form of physical microbial control?

Sterilization, Incineration

Three levels in controlling the growth of microorganisms

1. Sterilization 2. Disinfection 3. Antisepsis

How much time is required for a 2% glutaraldehyde solution to inactivate spores?

3-12 hours

Hexachlorophene

About 450 times more effective as a germicide than phenol.

Iodine

Control microbial growth by oxidizing certain molecules within the microbial cell, can also be used in the form of either a tincture or an iodophore.

Aldehydes

Group of organic compounds that control microbial growth by reacting with the proteins in microorganisms and altering their chemical structure.

Sterilization

Highest level of microbial growth control. Process of completely removing or destroying all life-forms, endospores, or their products on or in a substance.

What are the disadvantages of using bleach as a disinfectant?

Inactivated by organic matter and are corrosive.

Carbolic Acids

Joseph Lister first used phenol as a disinfectant during surgery to disinfect wounds.

Fungicides

Kill both fungi and their spores.

Should the refrigeration unit be used as a method of disinfection?

No, because it does not disinfect the body.

Cresols

Phenolic compounds derived from a chemical known as toluene. There are slightly different forms known as ortho-cresol, meta-cresol, and para-cresol.

Tincture

Solution of iodine and alcohol that is primarily used as an antiseptic.

Halogens

Widely used disinfectants that work by oxidizing the components of microbial cells.

Describe the control of microbes on a dead body placed in refrigeration unit prior to embalming?

Will inhibit growth of microbes while in the refrigeration, but will not kill the microbes once the body thaws.

Chlorine

Used to treat municipal drinking water and for the maintenance of swimming pools.

Benzalkonium Chloride

Topical antiseptic used on the skin before surgery, in nasal sprays to reduce the airborne transmission of disease in hospitals, and as a preservative in eye drops.