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Contaminants
Presence of microbes (pathogens & non-pathogens) in certain places we don't want them.
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Decontamination
The process of removing/destroying undesired microbes
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Resistance
The ability of microbes to withstand some type of decontamination/destruction
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What can we do to to effect the resistance of microbes to decontamination?
- Time of exposure to physical or chemical agent.
- Usually the longer we expose the microbes to the agent will increase its effectiveness.
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Which are the cell characteristics that may increase its resistance to decontamination?
- Endospores protect the bacteria from physical & chemical decontamination.
- Mycolic acid protects bacteria from many kinds of chemical decontamination
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What is the formation cells that makes them resistance to decontamination?
Biofilm/matrix
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In which genetic/metabolic activity phase decontamination likely to be most effective?
Log phase because the metabolic activity and growth is fastest which makes the bacteria to ingest other chemicals other then nutrients.
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Which decontamination method can we use to destroy/kill all microbes/cells?
- Sterilization
- Often also refers as "cidal" method
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Which decontamination method should we use to keep the number of bacteria low enough, so they won't make us sick?
- Sensitization
- Often times refered as static method
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Which are the different categories of physical decontamination methods?
- Temperature cold & hot
- Radiation ionizing & non-ionizing
- Filtration remove microbes but not toxins
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What is the purpose of using cold temperature as method of contamination?
To keep microbes from growing but not to kill them
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What is the purpose of using hot temperature as method of contamination? Which are the different categories?
- Kill all microbes spores included or keep them from growing.
- Moist heat: autoclave, non-pasteurizing steam, boiling, pasteurization.
- Dry heat: ovens and incineration.
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What damage "ionizing radiation" may cause to cells?
What is the source of it?
- Ionizing radiation cause electron ejection from molecules. It can cause bonds to break up, incorrect bonds, or release of toxins that lead to the death of the cell.
- X ray & gamma ray
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What damage "non-ionizing radiation" may cause to cells?
What is the source of it?
- Non-ionizing radiation moves electrons around the molecule but not eject them. As result, abnormal bonds will form in the molecule that will effect its function and shape.
- UV light
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How we may use "non-ionizing radiation" as decontamination?
- Water treatment: drinking & sewage
- disinfecting nonporous substances
- Personal products
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How may we use "ionizing radiation" as decontamination?
Food preservation
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When may we use "filtration" as decontamination?
To remove microbes from air & liquids in cases that other methods cannot be used.
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Which forms of chemicals can be used for decontamination?
Liquids, gases, and solids
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In which ways chemicals that are used in decontamination can damage cells?
- Digest and break down cell walls.
- Effect the permeability or make big holes in the cell membrane.
- Bind to DNA and interfere with its ability to replicate, make proteins, or breaking it apart.
- Denture proteins that change their structures a functions.
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Define disinfectants?
What they are used on?
- Kills only vegetative microbes (not spores)
- Used on non-living things (EX: Bleach)
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Define antiseptics?
What they are used on?
- Chemical that prevent growth of microbes but doesn't kill them
- Used on the surface of the skin or inside the body
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Define sterilant?
What they are used on?
- A chemical that kills everything including spores.
- Used only on non-living things
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Define degermer?
What they are used on?
A chemical that is used for removing microbes and debris from the body and often not even kill them.
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Define preservative?
What they are used in?
- Chemical that keeps microbes from growing in foods and medicines.
- Used in non-living things
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Halogens
- Chlorine: a disinfectant that breaks down S to S and S to H bonds in proteins causing the proteins to fall apart.
- Iodine: an antiseptic that enter the cell and interfere with its metabolism and different components especially sulfur bonds in proteins
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Cell membrane inhibitors
Polymyxins: polymyxin B sulfate
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Cell wall inhibitors classes and drugs examples
- Bete-lactam: penicillins & cephalosporins
- Non-beta lactams:Vancomycin & bacitracin
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DNA/RNA inhibitors drugs class & example
- Class: Fluroquinolones
- drug ex: Ciprofloxacin
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DNA/RNA inhibitors drugs are bind to which enzyme on gram (-) and gram (+)?
- Gram -: Gyras
- Gram+: Topoisomerase
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Aminoglycosides class drags examples
On which structure they will work?
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Protein inhibitors class of drugs that work on tRNA & m RNA? What side effects they have
Tetracyclines: EX: Doxycycline
Stain teeth, effect developing bones, GI tract problems in adults.
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Protein inhibitors class of drugs that work on bonds between amino acids? What side effects they have
Chloramphenicol
Can cause plastic anemia in some people
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Protein inhibitors class of drugs that work on 50S part of ribosome and bonds between amino acids? Give example drugs
- Marolides:
- Erythromycin, clarithromycin, and azithromycin
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Metabolism inhibitors class of drugs.
What is the specific substance these drugs interfere with?
- Sulfa drugs
- Folic acid synthesis
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What type of decontamination heavy metals are used for?
antiseptic
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Which are the most common heavy metals that are used in decontamination?
- More common: silver sulfadiazine & silver nitrate
- Less common: metallic silver & colloidal silver
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Which diseases are caused by bacteria that get destroyed by soap?
Which bacteria can grow in soap dishes?
- Gonorrhea, meningitis, syphilis.
- Pseudomonas
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What are alcohol's the mechanism of action?
- denature proteins (if concentrate enough)
- damage cell membrane
- Dehydrate cells
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What are phenols mechanism of action?
What determine its action?
- Disrupting cell wall
- disrupting cell membrane
- Cause protein damage
- Inactive enzyme
- interfere with DNA
- The outside group of phenol determine its MOA
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What are iodine's mechanism of action?
- Interfere with metabolism & different components of the cell
- Effects enzyme function by binding to their active sites
- Effect sulfur bonds in amino acids
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What type of drug is Polymyxin B sulfate?
Against which type of bacteria it will work on?
- Cell membrane inhibitor
- Gram negative
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How does lysosome destroy cells?
Where it can be found?
- Break down peptidoglycan in cell wall
- Saliva & tears
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How does defensins destroy cells?
Entering to the cell membrane and pull lipid apart from each other. making big holes in the membrane.
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Pyrogen on gram negative
LPS
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What does fever do to our immune system?
Speeds up metabolism, increase enzyme function, increase phagocytes activity, and help uptake available iron in our blood.
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Which are the three steps of phagocytosis?
- Chemotaxis, binding, and ingestion
- Phagolysosome formation
- Destruction and elimination
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Which are the four steps of complement?
- Initiation
- Amplification
- Polymerization
- Membrane attack
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What is IFN's mechanism of action?
Which is the source of it?
- Interferon prevent viruses from replicate themselves.
- IFN can be made by our cells or given to us in a medicine
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Naturalization
- Antibody attaches to a virus and prevent it from attaching to our cells.
- Also inhibits some toxins
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Opsonization
Antibody attaches to a microbe and mark it so macrophage will be able to recognize it
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Complement fixation
Antibodies stuck to big protein complex in complement cascadeand help break down microbes
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Agglutination
Antibodies clump microbes together in big lumps making it easier for the body to fight them
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IgG
The most common antibody in our body that gives us long term protection
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IgA
Antibody that found in mucus and saliva. It traps microbes before they invade our body
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IgM
Antibody that produced at the first time we get infected with some microbe. It clamps the microbes together so the body can react to them
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IgD
Antibody in low level in our body that help IgM
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IgE
Antibody that produced in cases of allergy or worm infections
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Examples of live attenuated vaccines
- Varicella (chickenpox)
- Influenza (spray)
- Rotavirus
- MMR
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Examples of killed/inactivated whole microbe vaccine.
- Polio
- Hepatitis A
- Influenza injection
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Examples of subunit vaccines
- Hepatitis B
- Pertussis
- influenza injection
- Heamop
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Examples of toxoid vaccin
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