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34 Cards in this Set
- Front
- Back
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What is the definition of disinfectants?
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A compound which destroys or inhibits the growth of microorganisms on non-living objects. (Tables, walls, beds)
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What is the definition of antiseptics?
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A compound which destroys or inhibitis the growth of microorganisms on living tissue, like skin or mucus membranes. They are not meant for systemic use, unlike antibiotics.
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Which properties should the ideal antiseptic or disinfectant have?
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- Destroy or remove all pathogenic microorganisms- Act at low concentrations- Not destroy or harm the skin, mucus membranes or non-living materials- Not be systemically toxic for humans after absorption- No strong odor- Stable against air and light- Not staning objects or tissue- Cheap- Biologically degradable- Not becoming inactivated by organic materials like blood or pus.
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What does asepsis mean and when is it important?
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The state of being free from pathogens. Important in surgery to prevent infections.
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What is the meaning of sterilization?
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It is a technique which completely destroys or removes all microbial life, including spores and prions from the surface of an object or in a fluid.
It can be done by heating, steamning, radiation and filtration, and by chemicals. |
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What is the phenol coefficient?
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It is a measure of how high the bactericidal activity is of an antiseptic or disinfectant. It efficacy is compated to phenol's efficacy, and is measured as which concentration of the antiseptic must be applied to have the same bactericidal effect as phenol.
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Name the alcohol compounds used in disinfection
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Isopropanol and ethanol in 60-70 % concentration.
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Mechanism of action of alcohol and which pathogens can they kill?
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It denatures proteins and dissolves lipids.
They can eliminate all pathogens except spores and parasites. |
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When do we use alcohol as a disinfectant?
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They can be used on skin, mucus membranes and on surfaces with is not stained by biological material as they get inactivated by that. Are often combined with other antiseptics/disinfectants.
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Name a glycol and its use
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Triethylene glycol.
Used as aerosol to sterilize air. |
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Name aldehydes used in sterilization
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Glutarataldehyde and formaldehyde
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Mechanism of action and antimicrobial spectrum of aldehydes?
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They react with amino moieties of proteins, precipitating them.
They have the widest antimicrobial spectrum - bacteria, viruses, fungi and spores. |
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Use of aldehydes as disinfectants? Can they be used as antiseptics?
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They damage tissues, so they cant be used as antiseptics. They are allergenic and carcinogenic.
Glutaraldehyde is used to sterilize surface and equipment. Formaldehyde gas is used to sterilize rooms. |
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Name phenol and phenol derivatives
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Phenol, cresols, hexachlorophene
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Use of phenol derivatives? Are they safe for use?
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They are used to disinfect equipment and surfaces.
Phenol was the first disinfectant ever, but only used on ingrown toenails because its irritating, corrosive etc. Hexachlorophene was used as disinfectant and in costemics, but was found to be neurotoxic. Cresol derivatives are used in strepsils. |
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Name a biguanide
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Chlorhexidine
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Mechanism of action of chlorhexidine? Is it effective against pseudomonas?
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It binds to and disrupts cell walls, causing leakage of intracellular components.
Not effective against pseudomonas |
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Use of chlorhexidine?
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Used for disinfection of the skin, mucus membrane. Can be used as mouth wash, but it discolors the teeth since its yellow.
Can be used as a preservative Is often combined with alcohols. |
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Name chlorine compounds
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Chlorine, sodium hypochlorite
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Mechanism of action of chlorine?
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Oxidate and denaturate DNA, RNA and proteins.
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Antimicrobial spectrum and use of chlorine compounds?
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It can be used against bacteria, viruses, fungi and spores. Their antimicrobial activity depends on the pH, but they are active at physiological pH.
Hypochlorite is used to disinfect equipment and surfaces, while chlorine is used to sterilize water. |
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Name iodine and its compounds
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Lugols iodine, iodophors like povidone-iodine
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What is iodophors and Lugol's iodine?
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Iodophors are combinations of iodine and a solubilizing agent.
Lugol's iodine is a mix of: iodine, potassium iodine and water |
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Mechanism of action of iodophors?
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They halogenate and damage DNA, RNA and proteins
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Use of iodines?
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They are used in antisepsis of skin and mucous, like in preoperative antisepsis.
Lugol's iodine is also used to gram stain. |
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Name oxidizing agents
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Hydrogen peroxide, benzoyl peroxide, ozone, peracetic acid.
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Mechanism of action of oxidizing agents?
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Catalase reacts with peroxides, releasing free radicals which damage lipids, proteins, DNA and RNA
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Use of oxidizing agents?
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Hydrogen peroxide: antiseptic and disinfectant. Bleaching agent. Contact lens cleaning. Cant be used on surfaces stained by biological material.
Benzoyl peroxide is used in anti-acne creams. Ozone: sterilization of air and water Peracetic acid: Sterilizes equipment |
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Name heavy metals used in disinfection
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Inorganic mercury, thiomersal (organic mercury), silver, zinc oxide
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Mechanism of heavy metals?
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They bind to sulphur and nitrogen in proteins, precipitating them. Its called the oligodynamic effect.
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Use of heavy metals?
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Thiomersal is good for preservation of vaccines, but not used in North America and Europe due to anti-vaccination movements saying its not safe.
Silver is used to increase efficacy of vaccines and antibiotics. Zinc oxide is used in deodorants and sunscreen |
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Use of quarternary ammonium compounds and why are they different from regular detergents?
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They are cationic detergents, unlike regular which are anionic.
They are often combined with chlorhexidine to increase the effect by reducing the surface tension. Can also be used alone to clean equipment and surfaces. They get inactivated by soap. |
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Name urinary antiseptics
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Methenamine, mandelic acid, nalidixic acid.
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Mechanism of action and use of urinary antiseptics?
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They are given systemically. Methenamine releases formaldehyde when in acidic environment like urine.
It cannot treat UTIs, but it can be used to prevent them. |
