L8 - Chemical and Physical Control Flashcards

These flashcards cover various methods of physical and chemical microbial control, including sterilization levels, medical device classification, and specific chemical agents.

Sterilization

The complete removal or destruction of all viable microorganisms, including bacterial endospores, typically used on inanimate objects.

Disinfection

The destruction or removal of vegetative pathogens but not bacterial endospores; usually used only on inanimate objects.

Antisepsis

The application of chemical agents to body surfaces to destroy or inhibit vegetative pathogens.

Decontamination/Sanitization

Any cleansing technique that mechanically removes most microbes and debris to reduce contamination to safe levels.

Mesophilic bacteria

The primary targets of microbial control; microorganisms adapted to live at environmental and/or body temperature that may cause infection or spoilage.

Bacterial endospores

The most resistant microbial forms; their destruction is the primary goal of sterilization as any process that kills them will kill all other forms.

Germicide

A general term for chemical agents that kill microorganisms.

Bactericide

A chemical agent that destroys bacteria except for those in the endospore stage.

Virucide

A chemical agent used to inactivate viruses, especially on living tissue.

Sporicide

A chemical agent capable of killing endospores.

Bacteriostatic

Agents that prevent the growth of bacteria on tissues or objects without killing them; the suffix -stasis means "to stand still."

Critical medical devices

Devices expected to come into contact with sterile tissues.

Semi-critical medical devices

Devices that come into contact with mucosal membranes.

Noncritical medical devices

Medical items that do not touch the patient or are only expected to touch intact skin, such as bedding and towels.

Native state

The normal three-dimensional configuration of a protein that allows for proper biological function.

Denature

The disruption of a protein's secondary or tertiary structure by breaking bonds via heat, pH, or solvents, rendering it nonfunctional.

Moist heat

Microbial control using hot water, boiling water, or steam ranging from $60^\text{o}\text{C}$ to $135^\text{o}\text{C}$ to coagulate and denature proteins.

Dry heat

Heated air with low moisture ranging from $160^\text{o}\text{C}$ to several thousand degrees that oxidizes cells and burns them to ashes.

Pasteurization

A technique for beverages involving heat at $71.6^\text{o}\text{C}$ for $15\text{ seconds}$ or $63^\text{o}\text{C}$ to $66^\text{o}\text{C}$ for $30\text{ minutes}$, used to reduce microbial load.

Tyndallization

A disinfection method for media with heat-sensitive components that involves intermittent exposure to steam without pressure.

Geobacillus stearothermophilus

The organism whose spores are used as the standard for determining the adequacy of sterilization processes.

Listeria monocytogenes

A specific pathogen that is notable for its ability to grow at refrigeration temperatures.

Lyophilization

A method of microbial control that involves freezing and drying to preserve microorganisms.

Ionizing radiation

High-energy radiation, such as Gamma rays and X-rays, that removes electrons from atoms and molecules.

Nonionizing radiation

Ultraviolet (UV) radiation that causes adjacent thymine residues in DNA to crosslink, preventing protein synthesis.

HEPA filters

High-efficiency particulate air filters used to mechanically remove airborne contaminants in environments like airplanes and respirators.

Plasmolysis

The disruption of the bacterial membrane caused by the hypertonic environment created by adding high amounts of salt or sugar to food.

Chlorhexidine

A chemical agent that targets most bacteria, some viruses, and fungi with low toxicity and long-lasting residual effects.

Glutaraldehyde

A sporicidal chemical used in health care that is high in activity and not inactivated by organic matter, though it is unstable.

Ethylene oxide gas

A high-activity, sporicidal gas used for sterilization; it has good penetration but is explosive and carcinogenic.