Microbiology Chapter 23

Betadine

A compound of iodine and a surfactant such as a detergent that can slowly release free iodine

Formalin

A concentrated liquid form of formaldehyde used as a disinfectant , in which HCHO gas is dissolved in water

Ultraviolet Light

A form of non ionizing radiation that can effectively control the growth of microorganisms placed directly in its path

Scrubbing

A manual process by which microorganisms are removed from a surface

Benzalkonium Chloride

A topical antiseptic used on the skin before surgery, in nasal sprays and as a preservative in eye drops

Alcohols

Act as surface tension reducers and are mostly used on skin as an antiseptic. Known to kill most vegetative cells, but not spores. Active against the tuberculosis organism.

Phenolic Compounds

Act by disrupting the cell membrane, causing bacterial lysis (decline of disease process) and inactivating essential enzymes and proteins.

How Bleach Works

Acts by liberating free Cl and the subsequent oxidation of essential cellular enzymes and proteins. These might also act on the cell membrane to adversely affect the diffusion of nutrients or wastes via. the cell.

Bactericides

Agents that destroy bacteria but not necessarily their spores.

Fungicides

Agents that destroy fungi and their spores

Larvicides

Agents that destroy insect larvae

Insecticides

Agents that destroy insects.

Viricides

Agents that destroy viruses

Sporicides

Agents that kill bacteria and mold spores

Ceepryn Chloride (Cepacol)

Found in throat lozenges. Disadvantages may cause respiratory irritation, birth defects in pregnant women.

Halogen Properties

Strong oxidizing properties and are very effective in controlling microorganisms

Germicides

Substances that destroy microorganisms, but not necessarily their spores

Disinfection

The destruction of infectious agents by chemical or physical means directly applied to an inanimate object. The destruction or inhibition of disease-causing microorganisms by chemical or physical means.

Thermal Death Point

The lowest temperature at which all microorganisms are killed in ten minutes

Thermal Death Time

The minimum time it takes to kill all microorganism present by heat

Antiseptics

The process by which microbial growth is inhibited on living tissue to prevent infection

Sterilization

The process of completely removing or destroying all life forms or their products on or in a substance

Halogens

The six elements found in the next to the last column on the far right side of the periodic table

Decimal Reduction Time

The time in minutes it takes by heat to kill 90% of the present microorganisms

Disadvantages to Alchols

Volatile and flammable, are inactivated by organic matter and not capable of killing some pathogens or spores

Aldehydes

Chemicals that react with the amino acids and hydroxyl groups in organic compounds. They inactivate proteins and nucleic acids and are strong reducing agents.

Halogens most widely used as disinfectants

Chlorine and Bromine

Disinfectant

Destroys or inhibits disease causing microorganisms; kills most vegetative microorganisms, but does not inactivate microbial endospores

Joseph Lister

First used phenol as a disinfectant during surgery to disinfect wounds

The Halogens

Fluorine(F), Chlorine (Cl), Bromine (Br), Iodine (I) and Astatine(At)

Disadvantage of Cl Compounds

Inactivated by organic matter and are corrosive in nature

Hypochlorites

Bleaches

Freezing

Both refrigeration and freezing are commonly used to preserve food by reducing microbial growth in cold environments.

Types of Disinfectants

Hypochloride, alcohol, aldehyde

Heat

Kills microorganisms by denaturing the proteins they contain

Cresol (lysol)

Molecules look like phenol but have methyl groups attached. Crude cresols from colloidal (milky) suspensions in water are good disinfectants because each colloidal droplet contains concentrated cresol.

Idiophones/Iodines

Non-irritating, non-staining, virtually odorless and very effective solutions of organic compounds of iodine. They combine actively with amino acids affecting the structural change in the pr steins made from the iodinated amino acids. It kills bacteria, molds and some viruses quickly by altering key protein molecules such as enzymes.

Concentration

Optimum concentration for disinfectant activity must be rigorously followed.

Antisepsis

Preventing or inhibiting the growth of pathogenic microorganisms

Sanitation

Process to promote and establish conditions which minimize or eliminate biohazards

Hexachlorophene

Retains a residual antibacterial dactivity after use and is a good skin degerming agent. May only be purchased via a prescription.

Quaternary Ammonium Compounds

also known as quits, commonly used as a topical antiseptic before surgery, in nasal sprays to reduce airborne transmission of disease.

Glutaraldehyde

an effective disinfectant and is actually a cold chemical sterilant when activated in a 2 percent solution.

Cremation Temperature

approximately 1600F

Disadvantages of Aldehydes

corrosive, irritating to skin and senses.