Ch. 14 Control of Microbial Growth Flashcards
Sterilization is
the most extreme protocols; complete removal or killing of all vegetative cells, endospores, and viruses from targeted item or environment
How can sterilization be accomplished?
physical: exposure to high heat, pressure or filtration
chemical: sterilants – kill all microbes and viruses and with the appropriate time endospores
What infection could potentially result as a failure to adhere to aseptic techniques?
Sepsis: inflammatory response to infection that results in high fever, increased heart and respiratory rates, shock and possibly death
Sterile field
created according to protocols requiring the use of sterilized materials such as: packaging and draping, strict procedures for washing and application of sterilants
Compare protocols for control of microbial growth
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disinfection
inactivates most microbes on the surface of a fomite by using antimicrobial chemicals or heat
- some microbes remain therefore disinfected item is not sterile
- endospores survive while all vegetative cells have been killed
antiseptics & example
antimicrobial chemicals safe for use on living skin or tissues
ex) hydrogen peroxide
how do alcohols work?
they work rapidly by denaturing proteins which inhibits cell metabolism and disrupting membranes which leads to cell lysis
-work better in aqueous solutions: alcohols coagulate proteins
when does alcohol coagulate proteins?
in higher alcohol concentrations, rapid coagulation of surface proteins prevents effective penetration of cells
What organisms can alcohol kill?
bacteria, fungi, and some enveloped viruses
Downside of alcohols
highly volatile which limits their effectiveness to immediately after application
Surfactants & example
chemical compounds that lower the surface tension of water
ex) soaps and detergents
How does a surfactant work chemically?
soaps are salts of long-chain fatty acids and have both polar and non-polar regions which allows them to interact with polar and non-polar regions in other molecules
Are soaps antiseptics or disinfectants?
NO: soaps do not kill or inhibit microbial growth
- “carry” away microorganisms, decontaminate
Quaternary Ammonium salts (quats) characteristics
- have hydrophilic and hydrophobic ends
- ability to insert into the bacterial phospholipid bilay and disrupt membrane integrity = death of cell
- cationic charge of quats = antimicrobial properties
