Aseptic Technique and Microbial Control

This set of vocabulary flashcards covers aseptic techniques, methods of sterilization (heat, radiation, filtration, chemical), and the principles of disinfection and antisepsis as presented in the lecture.

Antisepsis

The prevention of infection or exclusion of unwanted microorganisms; a technique developed from Joseph Lister’s use of carbolic acid.

Asepsis

A condition that is free of living organisms, including spores.

Aseptic Technique

Methods used to control, exclude, or eliminate unwanted microorganisms, also called contaminants, from specimens and test procedures.

Normal flora

Microorganisms present at non-sterile body sites that can contaminate specimens, hide suspected pathogens, or make isolation difficult.

Sterilization

The complete destruction or elimination of all microorganisms, including cells, spores, and viruses, in both their vegetative and spore phases.

Disinfection

The process of killing or removing pathogenic microorganisms from nonliving objects, though it does not necessarily destroy all living organisms or bacterial spores.

Moist Heat

The most economical and practical method of sterilization which kills microorganisms by denaturing proteins in the cells.

Autoclaves

A large metal pressure cooker that uses steam under pressure ($121.5^\circ\text{C}$ for $20$ minutes at $15\,\text{psi}$) to destroy microbial life, including endospores.

Dry Heat

A sterilization method that kills microorganisms similarly to moist heat but is less effective; includes incinerators, flaming, and hot air ovens.

Hot Air Oven

A device used for dry-heat sterilization of items that cannot withstand autoclaving, typically at $160^\circ\text{C}$ for $2$ hours or $170^\circ$ to $180^\circ\text{C}$ for $1$ hour.

Ionizing Radiation

A sterilization method using gamma rays or high-energy particles produced by radioactive cobalt that penetrate deeply.

Non-Ionizing Radiation (UV light)

A method that interferes with microbial DNA and has low penetrating ability; it only kills through direct exposure and is used for air and surfaces.

Filtration

The passage of fluid or air through a barrier with pores small enough to remove bacteria and viruses; used for heat-sensitive materials like vaccines.

HEPA filter

A high-efficiency particulate air filter found in biological safety cabinets to protect workers and filter air entering or exiting a room.

Chemical Sterilization

A process using hazardous chemicals like hydrogen peroxide or bleach, which must be diluted $60\text{--}90\%$ in water to effectively denature proteins.

Disinfectants

Chemicals used on inanimate (non-living) items that are not typically sporicidal.

Exposure Time

The specific amount of time a disinfectant must remain in contact with a surface to effectively work.

Antiseptics

Dilute disinfectants or chemical agents used on animate (living) objects, such as skin, to kill some organisms and interfere with the growth of others.

Bactericidal

A term indicating that bacteria are killed in the process.

Bacteriostatic

A term indicating that the growth of bacteria is inhibited, stopped, or slowed, but they may not be killed.

Microbial control

The measures taken to minimize the growth of microorganisms, commonly used in infection control protocols.

Protein denaturation

The breakdown or destruction of normal protein structure, leading to a loss of function and the destruction of the organism.

Sanitizer

A chemical agent primarily used for cleaning that only decreases the total number of organisms present.

Sporicide

An agent that is lethal to bacterial spores.

Viricide

An agent that is lethal to viruses.

Phenols and Chlorhexidine

Disinfectant groups that work by disrupting or changing the nature of the cell membrane.

Alcohols

Disinfectants like isopropanol and ethanol that change cell proteins and dissolve fats; $70\%$ concentration is more effective than pure alcohol because water is required.