Microbiology Exam 2 Content

Chapters 23 & 24

Disinfection

Reduces or destroys the microbial load of an inanimate item through the application of heat or antimicrobial chemicals.

Sanitization

Reduces microbial load of an inanimate item to safe public health levels through application of heat or antimicrobial chemicals.

Sterilization

Completely eliminates all vegetative cells, endospores, and viruses from an inanimate item.

Antisepsis

Reduces microbial load on skin or tissue through application of an antimicrobial chemical.

Degerming

Reduces microbial load on skin or tissue through gentle to firm scrubbing and the use of mild chemicals.

Scrubbing

The manual process by which microorganisms are removed from a surface.

Temperature

The use of incineration, dry heat, moist heat, free flowing steam, steam under pressure.

Dry Heat

Can only be used on items that can withstand the high temperature.

Moist Heat

Boiling at 212 degrees Fahrenheit for 10 minutes sterilizes water but does not kill endospores.

Free-Flowing Steam/Fractional Sterilization

Use on item for 30 minutes on successive days.

Steam Under Pressure

Most effective method at 15 psi, 250 degrees Fahrenheit, 15 minutes, kills everything including endospores.

Cold

Slows microbial growth but does not kill microorganisms.

Light

Ultraviolet (UV) light is a form of nonionizing radiation that can effectively control the growth of microorganisms placed directly in its path, damages cell’s genetic material.

Germicide

Kills a variety of microorganisms, but not their spores.

Bactericides

Kills bacteria but not their spores.

Fungicides

Kills both fungi and their spores.

Virucides

Inactivates viruses.

Halogens

Widely used disinfectants that oxidize the components of microbial cells or react to cellular proteins. Ex: Chlorine, Iodine.

Chlorine

Used to treat water. Gas combined with water to form sodium hypochlorite (bleach), strong chemical but requires long exposure to kill endospores.

Iodine

Usually used as a tincture or iodophor, antiseptic but doesn’t kill endospores.

Alcohols

Widely used disinfectants that control microbial growth by denaturing proteins and dissolving lipids in the cell membrane. volatile (easily vaporized) before germicidal effects can occur.

Aldehydes

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

Phenolic Compounds

Includes phenol, cresols, and hexachlorophene. Controls microbial growth by denaturing proteins and disrupting cell membranes. Not a good sterilant, doesn’t kill bacterial endospores.

Phenol

Flammable, sickly sweet and tarry odor, causes chemical burns, liver damage, diarrhea, dark urine, and hemolytic anemia. derivatives have replaced it in disinfectants.

Cresols

Phenolic compounds derived from toluene, found in Lysol, deodorants and insecticides. Works well in the presence of other organic compounds. Ortho-cresol, meta-cresol, para-cresol.

Hexochlorophene

450x more effective than phenol, has been replaced by chlorohexidine but is available with a prescription.

Quaternary Ammonium Compounds

Damages the cellular membrane and denatures microbial proteins, alters surface tension of the cell, deactivated in the presence of soap and organic matter.