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83 Cards in this Set
- Front
- Back
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Microbes with the highest relative resistance are:
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bacterial endospores by far, the hardest thing to kill, 18x harder to kill than their vegetative form, spores are used as the goal for sterilization.
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Microbes with a moderate range of resistance are:
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-Pseudomonas: notorious for ability to grow in lots of different environments, ie. soap dishes, disinfectant bottles.
-Mycobacterium tuberculosis: because of its mycolic acid tends to be more resistant than your avg. bacteria -Staphylococcus aureus:more resistant than most bacteria because he can tolerate acid, salt, cold; hearty in environments he can grow in. -Protozoan cysts: comparing trophozoites & cysts; cysts are more hearty -Viruses: comparing naked & enveloped viruses; naked viruses are heartier. Enveloped viruses present that membrane as a target. |
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Microbes with the least amount of resistance:
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-most vegetative bacterial cells
-protozoan trophozoites -enveloped viruses (because they have a membrane we can attack) -fungal yeasts, spores and hyphae |
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a process that destroys all viable microbes, including viruses and endospores. (only an appropriate term for inanimate objects)
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Sterilization
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a process to destroy vegetative pathogens, not endospores. (only an appropriate term for inanimate objects)
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Disinfection
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any cleansing technique that mechanically removes microbes. (only an appropriate term for inanimate objects)
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Sanitization
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Combining terms: If you were scrubbing a work surface with an antimicrobial soap you would be:
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sanitizing & disinfecting at the same time
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reduces the number of microbes on the skin. (appropriate term for human body)
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Degermation
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chemical agents are applied to the body to destroy or inhibit vegetative pathogens. (appropriate term for human body)
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Antisepsis
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Combining terms: If you were washing your hands with antimicrobial soap you would be doing:
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degermation & antisepsis at the same time.
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the permanent loss of reproductive capability, even under optimum growth conditions.
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Microbial death
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redefine microbial death in simpler terms:
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microbial death means: even if you put the organism in optimum conditions, it still wouldn't grow.
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Factors that affect death rate:
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-Exposure time
-Type of organism -Microbial load (# of microbes in the culture) -Agent's action (microbicidal vs. microbistatic) -Environment (chemicals work better at different temps. -concentration of chemical (usually ↑ concentration is better, but not with alcohol) -organic matter (it bogs chemical down, you need more chemicals to kill microbe) |
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microbicidal means:
microbistatic means: |
microbicidal means: truly kills with a permanent loss of reproductive capability.
microbistatic means: stops growth, but doesn't kill. |
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usually the higher the concentration of antimicrobial chemical the better; the exception is:
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alcohol; alcohol needs some water to be effective, so 90% alcohol is more effective than 100%.
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Common antimicrobial targets:
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-cell wall
-cell membrane -cellular synthetic processes (DNA, RNA) -proteins (denaturing them) |
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Methods of physical control of microbes:
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-Heat
-Cold -Desiccation -Radiation |
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Type of heat to control microbes that includes the use of hot water or steam:
What is the critical temp? What it kills: How it kills: |
Moist heat
The critical temp is: 121°C/15psi/15min What it kills: microbes How it kills: denatures their proteins; microbicidal |
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type of technique for controlling microbes in liquids that are meant for consumption:
What is the temp? What it kills: How it kills: |
Pasteurization
The temp is: 66°C for 30 min or 71.6°C for 15 sec. What it kills: vegetative pathogens How it kills: denatures their proteins but it only achieves DISINFECTION, NOT STERILIZATION. |
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Dry heat, what are the 2 types?
What is the temp? What it kills: How it kills: |
-Dry ovens: 150-180°C
-Incineration: 800-6500°C = complete oxidation and combustion of cells What it kills: How it kills: |
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Describe cold temps for controlling microbes:
What it kills: How it kills: |
-only microstatic - slows growth of microbes
What it kills: only deadly for some |
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Describe desiccation:
What it kills: How it kills: |
Dehydrates cells, leads to metabolic inhibition
What it kills: How it kills: it doesn't, many cells will grow again once water is returned. |
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two types of radiation as a physical control of microbes:
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Ionizing radiation & non-ionizing radiation
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describe Ionizing radiation:
what does it kill: how does it kill: |
-has penetrating power
-uses Gamma rays, X-rays, cathode rays -sterilizes medical supplies & food products what does it kill: how does it kill: breaks DNA |
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describe nonionizing radiation:
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-little penetrating power
-UV light can sterilize air, water & solid surfaces. what does it kill: how does it kill: mutates DNA |
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what kind of mutations does UV light cause?
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thymine dimers
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Methods of mechanical removal of microbes:
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-filtering
-washing and scrubbing |
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the physical removal of microbes by passing a gas or liquid through a filter
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Filtration
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filtration is used for:
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air or heat sensitive liquids.
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HEPA =
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High Efficiency Particulate Air filter
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Washing & scrubbing provides what level of microbial control?
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sanitization (mechanically removes microbes from inanimate objects)
-can combine sanitization & disinfection to both kill and remove microbes. |
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washing & scrubbing to reduce the number of microbes on the skin:
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degermation
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the nine groups of chemicals to control microbes:
"David Could Always Play Heavy metal After Going Home High" |
Detergents & soaps
Chlorhexidine Alcohols Phenolics Heavy metals Aldehydes Gases Hydrogen peroxide Halogens |
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what was used to control microbes in the 1800s?
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lye and iodine solutions.
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2 most common halogens used for microbes include:
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chlorine & Iodine
Chlorine (breaksdown in sunlight) -denatures proteins and can be sporicidal Iodine - iodophors & tinctures (doesn't breakdown in water) -Denatures proteins -can be sporocidal |
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something dissolved in alcohol =
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tincture
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iodine attached to a polymer which slowly releases the iodine over time =
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iodophor
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polar molecules that act as surfactants:
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detergents
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what do surfactants do?
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they insert themselves into a membrane and rip the membrane apart; dissolves lipids. They have a pos. charge on one end and a hydrophobic end on the other.
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A particularly useful detergent that acts as a surfactant is called a:
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QUAT; quaternary ammonia compound.
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what do quats do?
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quaternary ammonia compounds act as surfactants that alter membrane permeability of some bacteria & fungi
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what do quats not work well against?
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endospores
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describe the structure of the quat?
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it has a pos. charge on one end and a hydrophobic side on the other.
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describe how quats work:
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their positively charged heads attach to the neg. charged membrane of bacteria and insert their hydrophobic tails. When enough of them attach to the membrane they rip it apart.
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How do phenolics work?
What do they work against? |
they disrupt cell membranes and denature proteins. They are bactericidal, fungicidal, virucidal, but NOT sporicidal.
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what is the Phenol Coefficient:
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PC = lowest concentration of new chemical that kills in 10 min. ÷ Results for phenol
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phenol =
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carbolic acid
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what are phenolics?
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derivatives of phenol but much less irritating to human skin.
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What group of chemicals for microbial control is Triclosan in?
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Phenolics; it is a phenolic
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What is the Phenol Coefficient used for?
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it is used to give a measure of a new chemicals effectiveness in relation to the original phenol.
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Chlorhexidine is a phenolic, he works as a surfactant just like all phenolics. He disrupts the cell membrane and denatures proteins. So why does chlorhexidine get his own category?
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because chlorhexidine is extremely mild. You can use it to on mucus membranes and on the eyes, wounds, and as a neonate wash.
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What % do ethyl & isopropyl alcohol need to be?
how does it kill: what does it kill: |
50-90% solution
how does it kill: acts as a surfactant & denatures proteins what does it kill: bactericidal, fungicidal, but not sporicidal. Also kills enveloped viruses. |
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Hydrogen peroxide:
how does it kill: what does it kill: |
weak (3%) to strong (25%)
how does it kill: produces highly reactive oxygen radicals that damage protein & DNA what does it kill: Broad microbicide and STRONG solutions are sporicidal |
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would a 5% solution of hydrogen peroxide kill spores?
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no, only strong solutions (25%) of H2O2 are sporocidal.
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Will a 3% solution of H2O2 kill facultative anaerobes and aerobes?
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no, their free radical protective enzymes will be able to handle it.
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endoscopes are used for:
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colonoscopies
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Heavy metals
how does it kill: what does it kill: |
Solutions of silver & mercury kill vegetative cells in very low concentrations.
how does it kill: inactivating proteins what does it kill: broad microbicide but NOT sporicidal. |
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aldehydes
how does it kill: what does it kill: |
Glutaraldehyde & Formaldehyde
how does it kill: by crosslinking to deactivate proteins & DNA what does it kill: broad microbicide and sporicidal. |
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Ethylene Oxide Gas
how does it kill: what does it kill: |
how does it kill: it is a strong crosslinking agent that inactivates protein and DNA
what does it kill: Sporicidal -used in foods (spices packages with ethylene oxide gas) |
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what physical agents are sporicidal?
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-autoclave
-dry ovens and incineration -ionizing radiation -nonionizing radiation (air, water & solid surfaces only) |
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what chemical agents are sporicidal?
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-Halogens: chlorine & Iodine
-Ethylene Oxide gas -Hydrogen peroxide (only strong solutions) -Aldehydes: Glutaraldehyde & Formaldehyde (particularly Glutaraldehyde) |
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what mechanical agents are sporicidal?
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-Filtration (liquid & air only)
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Moist heat - autoclave:
What does it kill: How does it kill it: |
What does it kill: everything (sterilization)
How does it kill it: denatures proteins |
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Moist heat - pasteurization
What does it kill: How does it kill it: |
What does it kill: vegetative pathogens (disinfection)
How does it kill it: denatures proteins |
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Dry heat- dry oven & incineration
What does it kill: How does it kill it: |
What does it kill: everything (sterilization)
How does it kill it: denatures proteins |
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Cold temperatures
What does it kill: How does it kill it: |
What does it kill: only thermophiles; microbistatic NOT microbicidal
How does it kill it: N/A |
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Dessication
What does it kill: How does it kill it: |
What does it kill: Nothing
How does it kill it: N/A |
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Radiation - Ionizing & Nonionizing
What does it kill: How does it kill it: |
Ionizing radiation
What does it kill: everything (sterilization) How does it kill it: breaks up DNA Nonionizing radiation What does it kill: has little penetrating power but can kill everything (sterilization) in air, water, & solid surfaces. How does it kill it: mutates DNA |
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Filtration
What does it kill: How does it kill it: |
What does it kill: can sterilize liquids & air.
How does it kill it: physically removes pathogen |
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Washing & scrubbing
What does it kill: How does it kill it: |
What does it kill: N/A (removes microbes from surface)
How does it kill it: N/A |
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Halogens- chlorine & Iodine
What does it kill: How does it kill it: |
chlorine & Iodine
What do they kill: everything (sterilization) How do they kill it: denature proteins |
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Detergents
What does it kill: How does it kill it: |
What does it kill: some bacteria & fungi
How does it kill it: rips apart their membrane (surfactant) |
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a quaternary ammonia compound is a type of one of these:
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a detergent
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Phenolics
What does it kill: How does it kill it: |
What does it kill: bacteria, fungi, viruses
How does it kill it: as a surfactant & denatures proteins |
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Chlorhexidine
What does it kill: How does it kill it: |
What does it kill: broad microbicide
How does it kill it: surfactant & denatures proteins. |
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Alcohols- ethyl & isopropyl
What does it kill: How does it kill it: |
What does it kill: bactericidal, fungicidal, & virucidal (only enveloped viruses)
How does it kill it: surfactant (dissolves lipids) & denatures proteins. |
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does alcohol destroy viruses?
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only enveloped viruses; NOT effective on naked viruses.
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Hydrogen peroxide
What does it kill: How does it kill it: |
What does it kill: broad microbicide
-strong solutions (25%) kill everything (sterilization) -weak solutions (3%) only kill anaerobes. How does it kill it: produces highly reactive oxygen radicals that damage protein & DNA |
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Heavy metals-silver & mercury
What does it kill: How does it kill it: |
What do they kill: broad microbicide (vegetative cells)
How do they kill it: by inactivating proteins |
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Aldehydes- Glutaraldehyde & Formaldehyde
What does it kill: How does it kill it: |
What does it kill: everything (sterilization)
How does it kill it: by crosslinking to deactivate proteins & DNA |
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Ethylene Oxide gas
What does it kill: How does it kill it: |
What does it kill: everything (sterilization)
How does it kill it: by crosslinking to deactivate proteins & DNA |
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what chemical agents taught specifically kill: bacteria, fungi, & viruses?
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Phenolics & Alcohol
(alcohol only kills enveloped viruses though) |
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what chemical agents taught specifically kill bacteria & fungi?
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detergents
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