Chapter 13: Controlling Microbes in the Environment

Antiseptic

Any substance that can be applied to human tissue to reduce sepsis (mouth wash)

Aseptic

Any method that gets rid of pathogenic organism to prevent patient from getting an infection

Sepsis

Systemic inflammation due to an infection that leads to fever, elevated heart and respiratory rates that lead to shock and death

Degerming

Removing microorganisms with soap

Disinfection

inactivates most microbes on the surface by using antimicrobial chemicals or heat (natural: vinegar; chemical: bleach)

Pasteurization

increasing temperature to partially kill microorganisms (milk)

Sanitation

Any method that keeps surfaces clean (cleaning bathroom, washing sheets)

Sterilization

Any methods that completely kills/removes all pathogens (autoclave)

How does a fungicidal differ from a fungistatic agent?

Fungicides: kill fungi

Fungistatic: prevents growth

2 ways antimicrobials work

Prevent cell wall synthesis

Prevent protein synthesis

Makes holes in membranes

Inhibit metabolic pathways

The ideal antimicrobials should be

Target only the microorganism but not the patient; have little or no side effects

2 factors affecting efficary of antimicrobials

Antibiotic concentration

How body responds to a antimicrobial (if it metabolizes quickly)

How does heat kill microbes?

Denatures microbe’s proteins, including enzymes. needed for all metabolic reactions

How does desiccation differ from lyophilization?

Lyophilization uses vacuum and cold temp; desiccation uses heat. Lyophilization retains better shape and rehydrates faster.

How does osmotic pressure stop microbial growth? What type of microbial growth survive well with high osmotic pressure?

-Cell shrink at high osmotic pressure

-Cell burst/swell at low osmotic pressure

-Halophiles

How does radiation kill microbes?

Creates mutation in genes; mutated genes make defective proteins

Thermal death point

Temperature needed to kill al microbes in 10 mins

Thermal death curve

Tells you time needed to kill 90% or microbes

Phenol

Disinfecting chemical that kills pathogens but irritates/damages tissue; Thymol & eucalyptol are naturally in some plants

Heavy metals

Inactivate essential proteins in microbes but doesn’t target pathogens only (toxic)

Halogens

Iodophore (Betadine) is a topical antiseptic used before surgeries

Chlorine compounds

Chemical disinfectant

Soaps

Emulsifiers (seperate fats)

Alcohols

Antiseptics & disinfectants (ethanol, isopropyl alcohol)

Dehydration

High salt (or sugars) concentration remove water from microbe