PHYSICAL + CHEMICAL CONTROL OF MICROBES CH 11 Flashcards
What are the two most resistant microbial types?
Are gram - or gram + bacteria more resistant?
- Prions and Bacterial Endospores
- Gram Neg- bacteria are generally more resistant than Gram Pos+ bacteria
What are the most resistant microbial entities
Bacterial endospores (not prions bc they are not living)
Compared to vegetative cells, what method are endospores MOST and LEAST resistant to?
MOST: Sporicidal Liquid (18x more resistant)
LEAST: Moist heat (1.5x more resistant)
Identify and describe the levels and categories of microbial control method from lowest to highest level of clean
DADS:
Decontamination: Reduces the amount of microbes present on living and nonliving surfaces
- Antisepsis and Disinfection kill all microbial life APART FROM BACTERIAL ENDOSPORES:
Antisepsis: Living Surfaces
Disinfection: Non-Living Surfaces
Sterilization: Destruction of ALL microbial life INCLUDING bacterial endospores
Sterilization:
Describe the level of clean. When is it used? What is an example of this method?
Kills ALL microbes (including bacterial endopsores)
- Critical Medical Intruments that go into tissues
- Autoclave uses pressure and heat to kill microbes
Disinfection:
Describe the level of clean. When is it used?
Kills all microbes APART FROM BACTERIAL ENDOSPORES
- It is used on non-living surfaces
Antisepsis:
Describe the level of clean. When is it used?
Kills all microbes APART FROM BACTERIAL ENDOSPORES
- It is used on living surfaces
Decontamination:
Describe the level of clean. What is an example of this method?
Mechanical removal that reduces the amount of microbes on living and non-living surfaces
- Soap or detergent to clean hands or clothes
Sepsis vs Asepsis vs Antisepsis
Sepsis: Containing microbes
Asepsis: PREVENTION of contamination
Antiseptic: Sterile methods that kill vegetative microbes on living surfaces AFTER CONTAMINATION
-Cidal vs -Static Agents
Cidal - Kills microbes (think of homocide)
Static - Stopping/slowing replication (fridge)
Identify and describe the different levels of medical devices and what cleaning method is best used on each
Critical Medical Device: Comes into contact with tissues; STERILE
Semi-Critical Medical Device: Comes into contact with mucosal membranes of the nose, eyes, ears and mouth; DISINFECT
Noncritical Medical Device: Only comes into contact with intact skin; Disinfect OR Decontamination
How would you classify the forceps used in neurosurgery? What control method would you use?
Critical Medical Device
Sterilization
What are the factors that affect the rate at which antimicrobial agents work on microbes
- The longer you let it sit, the more cells are killed
- Endospores take longer to kill
- The larger amount of microbes, the longer it takes to clean
What are the four targets for physical and chemical agents
- DNA/RNA
- Cell Wall
- Cell Membrane
- Proteins
What method is used to disinfect on living surfaces
Antisepsis
Put the following in order from most to least resistant:
- Fungal Spores
- Protozoan Cysts
- Gram Pos+ Bacteria
- Prions
- Prions
- Protozoan Cysts
- Fungal Spores
- Gram Pos+ Bacteria
Identify four methods of physical control
- Moist Heat
- Dry Heat
- UV
- Filtration
Moist vs Dry Heat Methods; Identify examples of each. Which is more effective?Why?
Moist Heat - Autoclave
Dry Heat - Incineration (fire)
Moist heat is more effective because it uses lower temps, and MUCH LESS time
How does the autoclave work? What method is this?
It combines heat, steam, and pressure to sterilize
- This is a moist heat, sterile method
Identify and describe the two dry heat methods
Incineration - Fire
Hot Air - Oven
Describe filtration methods. What is the highest level of clean you can get with this method?
Trapping pathogens and particles and filtering out water. Special filters that are small enough to trap viruses can get us to sterilization
How does a beard affect masks?
Maks becomes ineffective as it pushes it away from face and allows microbes and bacteria to pass in both directions
T/F: Lower temperatures can be used with dry heat than moist heat
False; moist heat uses lower temps
What is an aqueous solution
Chemical diluted in water
