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38 Cards in this Set
- Front
- Back
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Sterilization
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Remove all forms of microbial life
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Disinfection
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destruction of vegetative pathogens; used on inert, non-living surfaces
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Antisepsis
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destruction of vegetative pathogens on living tissue
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Sanitization
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lower the microbial count on surfaces – restaurants for example
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Aseptic Technique
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techniques used to prevent contamination
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Bacteriocidal
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– kills bacteria
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Bacteriostatic
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inhibits bacterial growth, Completly stops growth unitl removed
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Factors effecting Anitmicrobial activity
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Microbial Suscepibility
number of microbes concentration of agent environmental conditions (blood) length of exposure |
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Pastuerization
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Slow heating to kill potential food-borne pathogens but not alter the taste, e.g., milk
Classic Heat to 63oC for 30 min |
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High Temp short time pasteurization
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70 degrees C for 15 min
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Ultra High Temperature Treatment
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140 C for 1 second
European milk |
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How do you test disinfectant, antiseptic and perservative activity?
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disk diffusion test
dilution test |
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Autoclave
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15psi 121 c for 15min
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Ionizing radiation
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<1nm in wavelength
Ionizes water to create hydroxyl radicals or toxic forms of oxygen both of which react with DNA and other organic cellular components |
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Nonionizing radiation -
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1nm in wavelength
> UV for example – damages DNA by causing thymine dimers which inhibit DNA replication 260 nm most effective – germicidal lamps used in hospital rooms, operating rooms research labs. |
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filter sterilization
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seful for sterilizing fluids that cannot withstand autoclaving – organic supplements, antibiotics, enzyme solutions
Depends on pore size – 0.22 um for bacteria 0.01um for some viruses and large proteins |
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Physical methods of Controling microbial growth
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Heat-Protien denature
Direct flaming- incineration Filter-seperate from liquid Cold-decreases chem reactions High pressure-changes structure of proteins and Carbs Dessication-disrupts metabolism ossmotic pressure-plasmolysis Radiation-damages DNA |
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Lyophilization
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Water removed by vacuum or low temp, best for preserving cultures longterm
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What do Phenols and Phenolics target in bacteria?
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injure the plasma membrane
Lister first used _______as a disinfectant |
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What do bisphenols target in bacteria? What is an example of a bisphenol?
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Plasma membrane
Example: triclosans – antibacterial soaps – incorporated into cutting boards and counter tops – inhibits fatty acid biosynthesis – may increase antibiotic resistance in bacteria |
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What do Quaternary Ammonium compounds target?
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Quats – modification of four valent ammonium compounds
– action unknown but probably the plasma membrane |
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Alcohols target what?
Ideal concentration? |
denature proteins and / or disrupt membrane
Degerming – before a shot 70% is optimum concentration of ethanol – the 30% water seems to help its penetrating action |
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Halogen target
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iodine and chlorine – seem to interfere with protein function
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Heavy metal target
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denatures proteins
Silver used in newborns to prevent gonorrheal ophthalmia neonatorum |
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Aldehyde target
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Protein denature
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Gassous Chemosterilizer target?
Peroxygen action? |
protein denature
Oxidizing |
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Chemical food Preservatives
Orgainic acid Nitrites |
Organic-inhibits metabolism
Nitrites-inhibit iron containing enzymes |
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Who discovered penicillin?
What do penicillins affect? |
Alezander Flemming
Inhibit cell wall |
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Who founded chemotherapy and with what drug?
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Paul Ehrlich- salvarsan for siphalis
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What antibiotics work by inhibiting cell wall synthesis?
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Penicillins
Cephalosporins Bacitracin vancomycin |
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What antibiotics work by inhibiting protein synthesis?
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chloramphenicol
erythromycin tetracyclines Streptomycin |
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What antibiotics work by inhibiting neuclic acid replication and trascription?
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Quinolones
rifampin |
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What antibiotics work by inhibiting synthesis of essential metabolites?
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Sulfanilamides
trimethoprim |
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What antibiotics work by injury to plasma membrane?
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polymyxin B
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How does penicillin inhibit cell wall synthesis?
What is a broad spectrum derivative of penicillin? |
prevents cross linking of peptidoglycan
Ampicillin! |
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How has penicillin been changes to work better? 3 ways
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1. Acid resistance
2. Penicillinase resistance 3. broad spectrum |
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How does bacteria become resistant to antibiotics?
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Acquired by either mutation in the pathogen’s chromosome or by direct transfer of R-factor plasmids.
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Sensitive microbes may become resistant to a drug by gaining the ability to:
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Inactivate or destroy the antibiotic
Alter their own membranes Alter the target site Rapid efflux |
