Chapter 13 Study Guide Flashcards
Involves applying chemicals to living tissue to reduce microbes
Ex. Hydrogen peroxide, isopropyl alcohol
Antisepsis
Uses physical or chemical means to reduce the number of microbes on an inanimate surface
Ex. Bleach, vinegar, heat
Disinfection
Refers to practices and procedures that prevent contamination, maintain a sterile environment, reduce risk of infection during medical and surgical procedures.
Asepsis
Rely on moist heat sterilization, they are used to raise temperatures above the boiling point of water to sterilize items such as surgical equipment from vegetative cells, viruses, and especially endospores.
Autoclave
Kills bacteria
Kills viruses
Kill fungi
Bactericide
Viricide
Fungicide
Treatments inhibit the growth of bacteria
Treatments inhibit the growth of fungi
Bacteriostatic
Fungistatic
Agents prevent further growth but do not kill the microbe
Microbiostatic
Cationic molecules that disrupt cell membranes
Example: chlorhexidine
Effective against: gram positive, gram negative, yeast, enveloped viruses
Often used as a surgical scrub and mouthwash
Not effective against naked viruses, endospores, pseudomonas aeruginosa
Bisbiquanides
A sterilization method that involves steam and pressure
Temps above boiling point
Standard conditions : 121c at 15 psi
Routine testing must be done to ensure proper testing
Autoclaving
Categories of cleanliness
Critical
Semi critical
Non critical
Risk of introducing microbes directly into the body
Ex: surgical instruments, catheters, IV fluids
Critical
Contact with mucus membranes or broken skin
Ex: endospores, respiratory therapy equipment
Semi critical
Contact skin but do not penetrate
Ex: linens, stethoscopes, crutches
Non critical
Hand washing is an example of
Physical removal of microbes
Degerming
Involves removing sufficient microbes to reduce the risk of disease transmission
Commercial dishwashers
Cleaning protocols in healthcare facilities
Sanitization
Dehydration slows cellular metabolism, used to preserve foods (dried fruits, jerky) some microbes and endospores will remain
Desiccation
Items are flash frozen under a vacuum to remove moisture
Items can be stored at room temperature
Used both for foods and to preserve microbial cultures
Lyophilization
Is an inanimate object or surface that can carry and transfer infectious microorganisms, such as door knobs, towels, or medical equipment.
Fomite
A method of disinfecting liquids (not sterilizing) using heat
High temperatures short time (HTST)
72c for 15 seconds
Ultra high temperatures (UHT)
138c for > 2 seconds
Pasteurization
Was first used by Joseph lister as a surgical disinfectant
Contains a phenol group as part of their structure
Works by denaturing proteins and disrupting membranes
Phenolic
Lysol
Phisohex
Triclosan
Examples of phenolics
Effectively kill all microbes and viruses, and with appropriate exposure time, can also kill endospores
Sterilants
A ______ environment is completely free from all living microorganisms, including bacteria, viruses, fungi, and spores.
Sterile
Common methods of sterilization
Autoclaving
Dry heat
Chemical sterilization
The complete removal or killing of all vegetative cells, endospores, and viruses from the targeted item or enviorment
Sterilization
Why is maintaining good aseptic technique critical ?
Prevents contamination of sterile surfaces
Medical procedures that carry risk of contamination must be performed in a ______, a designated area that is kept free of all vegetative microbes, endospores, and viruses
Sterile field
______ reduces or eliminates most harmful microorganisms on surface or objects but does necessarily eliminate all spores whereas ______ destroys all microorganisms, including spores
Disinfection
Sterilization
Common methods of disinfection
Chemical disinfectants
Ultraviolet light
Boiling water
Anti microbial wipes
How does antisepsis differ from disinfection?
Antisepsis is used on living tissue
Disinfection is used on inanimate objects
Lowers surface tension of water
Found in soaps and detergents
Surfactants
What is difference between a method that is microbial and one that is microbiostatic ?
Microbial kills microorganisms outright, eliminating them from the environment
Microbiostatic methods inhibit the growth or reproduction of microorganisms
The microbial death curve within a population occurs at a
Constant rate
Amount of time to reduce the population by 90%
Decimal reduction time DRT
What are some physical methods of microbial control
Heat
Radiation
Pressure
Filtration
Desiccation
What considerations affect the choice of method ?
Degree of effectiveness
Availability
Cost
Time
Practicality
What is the difference between moist and dry heat ?
Moist heat involves water
Dry heat does not involve water
- Examples of dry heat
- Examples of moist heat
- Boiling and autoclaves
- Incinerators
Dry ovens
Fire
Which method is more effective, dry heat or moist heat ?
Moist heat because it penetrates cells better than dry heat
What does an autoclave use to achieve sterilization
Uses moist heat and under high pressure
Is refrigeration and freezing usually microbial or Microbiostatic
Microbiostatic, they inhibit growth and reproduction of microorganisms rather than killing them
Are Pasteurized fluids sterile
No
What will likely happen when the item is no longer being refrigerated in terms of microbial count?
The microbes will start increasing
In this form of therapy, a patient breathes pure oxygen at a pressure higher than normal atmospheric pressure, typically between 1 and 3 atmospheres
Hyperbaric oxygen therapy
Helps increase oxygen saturation in tissues that become hypoxic due to infection and inflammation
Hyperbaric oxygen therapy
How does desiccation inhibit microbial growth
By drying out
What can lyophilization be used for ?
Freeze drying
How does high salt or sugar in a food limit growth of microbes ?
Creates a hypertonic environment drawing water out of microbial cells
How is radiation able to achieve sterilization
By damaging DNA and RNA
Uses x rays, gamma, or electron beams
Can penetrate plastic & paper
Sterilizes by causing irreparable damage to dna
Can be used on heat sensitive materials as well as foods
Ionizing radiation
Ultraviolet light
Lower energy than ionizing radiation
Does not penetrate paper or plastic
Useful for disinfection
Non-ionizing radiation
What type of substances can filtration be used on?
Useful for air and heat sensitive liquids
Why is pore size an important consideration with filtration?
Microbes larger than the pores are trapped
How do heavy metals achieve disinfection
Inhibit enzymes by binding to proteins and causing denaturation
Common heavy metals
Mercury
Silver
Zinc
Copper
Oxidizes cellular components
Often used as an iodophor
Betadine
Iodine
Interferes with metabolism in bacteria that cause tooth decay
Also strengthens enamel
Fluorine
Chlorine gas
Sodium hypochlorite (bleach)
Hypochlorite salts
Chloramines
Chlorine
How do alcohols achieve disinfection
Denature proteins and disrupt membranes
Alcohols are not effective against
Naked viruses
Alcohols can be inhibited by
Dirt
Emulsifies dirt and other particles which are then rinsed away
Soaps
Also amphipathic
More soluble in hard water
Includes anionic detergents and quats
Detergents
Similar in structure to phospholipids
Can disrupt membranes
Useful as antiseptics and disinfections
Quats
Quarternary ammonia salts
Cationic detergents
How do bisbiguanide achieve disinfection.
Cationic molecules that disrupt cell membranes
Formaldehyde and Glutaraldehyde are used as chemical sterilants
Aldehydes
What kind of gas can be used as a sterilant
Ethylene oxide
Creates free radicals that damage DNA, most common peroxygen
Hydrogen peroxide
