tsikhngl5 Flashcards
Sterilization
Removal or destruction of all microorganisms and viruses in/on a product
Disinfection
-Elimination of most or all pathogens on/in a material.
-Does not kill all microbes
Sanitization
lowering the microbial counts to a safe level to meet public health standards
Degerming
removal of most microbes from a limited area
Cidal vs Static
Cidal: Kills microbes (e.g., bactericidal).
Static: Stops growth of microbes (e.g., bacteriostatic).
Antisepsis (Antiseptic)
Disinfection of skin or living tissue
Asepsis (Aseptic)
An area free of significant contamination.
Heat to Destroy Microbes
Methods: Boiling, pasteurization, autoclave, dry heat sterilization.
Boiling
Kills most pathogenic bacteria and viruses but not all endospores; disinfection
Pasteurization
Eliminates pathogens and lowers microbial numbers to slow spoilage
Autoclave
-A device that uses pressure and steam to sterilize materials
-Kills all endospores in about 15 minutes; best method for sterilization
-used on culture media, hospital instruments, materials that can withstand heat and moisture
Dry Heat Sterilization
-Destroys microbes by denaturing proteins
-Used for materials that are not moisture-sensitive.
-Direct flaming, incineration, hot air sterilization.
Hot Air Sterilization
a drying oven used for dry materials that are not temperature sensitive
Incineration
Effective way to dispose of contaminated materials
Direct Flaming
Used to sterilize inoculation needles and loops
Filtration
-Process of passing a liquid or air through a filter to remove microbes
-Used for sterilizing temperature-sensitive liquids and air in certain environments.
-Liquids: uses a vacuum
-Air: uses HEPA filters
Low Temperatures
Slows or stops microbial growth.
- in freezing, only small portion of microbes die
-bacteriostatic
High Pressure
Treatment of liquid suspensions with high pressure to kill bacterial cells
-bactericidal but does not kill endospores
Desiccation
Removal of water from microbes, slowing or stopping their growth
- Usually does not kill microbes but slows their growth (bacteriostatic)
Osmotic Pressure
Use of high concentrations of salts or sugars to create a hypertonic environment, killing or inhibiting microbial growth.
Radiation
Ultraviolet
- Destroys DNA
- Xrays and gamma rays penetrate
materials
- UV and high energy electron
beams used on surfaces
Microwaves
- Do not kill microorganisms
directly
- Heats water
- High temperatures can be used
to disinfect materials
Disk Diffusion Method
Disks soaked in disinfectant are placed on agar plates inoculated with bacteria, and effectiveness is determined by the zone of inhibition
Phenolic Compounds (Phenols)
Disrupts plasma membranes and denatures proteins (bactericidal)
- Suitable for disinfection of surfaces contaminated with saliva, pus, feces
-Examples: Lysol, Hexachlorophene, Triclosan.
Chlorhexidine (Biguanides)
Attacks plasma membrane (bactericidal) and controls microbes on skin and mucous membranes; only kills some viruses and not endospores
-Examples: Skin creams, disinfectants, mouthwash containing chlorhexidine.
Halogens
Destroys proteins and membranes (bactericidal) and are used as disinfectants and antiseptics
-Examples: Household bleach (chlorine), tincture of iodine, iodophor (Betadine)
Alcohols
Denature proteins and disrupt membranes; kills bacteria and fungi but not endospores and some viruses
-Examples: Ethanol (70% most effective), isopropanol (rubbing alcohol).
Heavy Metals
Silver Nitrate
- Eye drops for newborn against
Ophthalmia Neonatorum
Silver Sulfadiazine
- Cream for burns
Silver Ions
- Incorporated into bandages and
catheters to slow growth of
microbes
Copper Sulfate
- Used to inhibit algae in
reservoirs
Mercuric Chloride
- Used in paint to control mildew
Zinc Chloride
- Used as antiseptic in
mouthwashes
Quaternary Ammonium Compounds (Quats)
Kills most bacteria, fungi, and some viruses; does not kill endospores or some Gram Negative Bacteria
-example: Cepacol
Gaseous Chemo Sterilizers
Chemical gases used for sterilization and kills all microbes including endospores and viruses.
-Examples: Ethylene oxide.
Oxidizing Agents
Used as antiseptics, disinfectants, and for water treatment to oxidize and denature proteins
-Examples:
Hydrogen Peroxide (antiseptic for wounds)
Ozone (used w/ chlorine to disinfect water)
Benzoyl Peroxide (antiseptic on skin)
-Kills anaerobic bacteria living in
tissues (bacteria that can cause
acne)
