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56 Cards in this Set
- Front
- Back
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What is the process by which all living cells, spores, and acellular entities (e.g., viruses, viroids, and prions) are either destroyed or removed from an object or habitat? |
sterilization
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What is the killing, inhibition, or removal of microorganisms that may cause disease? |
disinfection |
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What is the substantial reduction of the total microbial population and the destruction of potential pathogens? |
disinfection
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What are disinfectants typically used on? |
inanimate objects |
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What may remain after using a disinfectant? |
viable spores and a few microorganisms |
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In what is a microbial population reduced to levels that are considered safe by public health standards? |
sanitation |
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What is the destruction or inhibition of microorganisms on living tissue? |
antisepsis |
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What are chemical agents applied to tissue to prevent infection by killing or inhibiting pathogen growth? (They also reduce the total microbial population.)
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antiseptics |
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What suffix do substances that kill organisms often have? |
-cide |
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What kill pathogens but not necessarily endospores? |
cidal agents |
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What suffix do substances that halt growth often have? What happens when they're removed?
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-static
growth will resume |
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At what rate does population death occur?
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exponential (logarithmic) |
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Why may the rate of killing slow when a population has been greatly reduced?
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the survival of a more resistant strain of the microorganism |
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What is a precise measure of an agent's killing efficiency? |
decimal reduction time (D value) |
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What is the decimal reduction time? |
time required to kill 90% of the microorganisms or spores in a sample under specified conditions
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When would cells be referred to as viable but unculturable (VBNC)?
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if they can't reproduce |
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What are the two most frequently employed physical agents to control microbial growth and sterilize objects? |
heat and radiation |
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Does boiling disinfect or sterilize? |
Disinfect, it doesn't kill spores.
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What does destroying bacterial endospores require? |
temperatures above 100 degrees Celsius and the use of saturated steam under pressure |
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What is steam sterilization carried out with? |
autoclave |
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What does microbial death result from? (2) |
oxidation of cell constituents and denaturation of proteins |
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What wavelength of radiation is quite lethal? |
around 260 nm (UV)
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What prevents replication and transcription? How? |
UV radiation by causing thymine-thymine dimerization |
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Why does the ideal disinfectant have a low surface tension? |
so it can enter cracks in surfaces
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What are meant to be used whenever thorough cleaning with soap and water will be delayed? |
antiseptics
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What are used as disinfectants in laboratories and hospitals? |
phenol and phenol derivatives |
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How do phenolics act? |
by denaturing proteins and disrupting cell membranes |
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What are among the most widely used disinfectants, antiseptics, and sanitizers?
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alcohols |
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Are alcohols bactericidal, fungicidal, or sporadical? |
bactericidal and fungicidal
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What form saltlike compounds with sodium and most other metals? |
halogens
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What halogens are important antimicrobial agents? |
iodine and chlorine |
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What halogen is used as a skin antiseptic and kills by oxidizing cell constituents?
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iodine |
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What are many heat-sensitive items such as disposable plastic Petri dishes and syringes, heart-lung machine components, sutures, and catheters sterilized with?
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ethylene oxide |
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What is a very strong alkylating agent that kills by reacting with functional groups of DNA and proteins to block replication and enzymatic activity? |
ethylene oxide
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What is a particularly effective sterilizing agent because it rapidly penetrates packing materials, even plastic wraps? |
ethylene oxide |
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What is the process of heating a temperature sensitive liquid to temperatures below boiling for the purpose of killing undesirable microbes? |
pasteurization |
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How does pasteurization preserve beverages? |
It kills pathogens and reduces the level of non-pathogens. |
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What sterilizing tool resembles an autoclave in appearance?
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ethylene oxide sterilizer |
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What fumigation is used in the food industry to sanitize fruits and vegetables of contaminating yeasts and molds?
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ClO2 fumigation |
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What fumigation is best known for its use in sterilizing the U.S. Senate and Postal facilities after the 2001 anthrax attacks? |
ClO2 |
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Why does a larger population require a longer time to die than does a smaller one? |
an equal fraction of a microbial population is killed during each interval |
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What is the best-known disinfectant screening test? |
phenol coefficient test
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What is used to calculate the phenol coefficient? |
The highest dilution (lowest concentration) that kills the bacteria after a 10-minute exposure but not after 5 minutes. |
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What is the relationship between phenol coefficient value and disinfectant effectiveness? |
the higher the phenol coefficient value, the more effective the disinfectant under the test conditions
A value greater than 1 means that the disinfectant is more effective than the phenol. |
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What is a method of evaluating disinfectant effectiveness at a recommended dilution? |
use dilution test |
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What is tyndallization? |
intermittent sterilization |
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How do dry air heat and moist heat compare for sterilization? |
Moist heat is more effective. |
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What can be used to sterilize powders, oils, and does not corrode glassware?
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dry heat |
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What is slow and not suitable for heat-sensitive materials such as many plastic and rubber items? |
dry heat
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What are benzalkonium chlorid and cetylpyridinium chloride?
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cationic detergents |
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What kill most bacteria but not M. tuberculosis or spores? |
cationic detergents |
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What have the advantages of being stable and nontoxic, but are inactivated by hard water and soap? |
cationic detergents
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What are often used as disinfectants for food utensils and small instruments and as skin antiseptics? |
cationic detergents
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What are highly reactive molecules that combine with nucleic acids and proteins and inactivate them, probably by cross-linking and alkylating molecules? |
aldehydes |
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What are quaternary ammonium compounds?
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detergents
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What is an organic molecule other than soap that serves as a wetting agent and emulsifier and may be used as an antimicrobial agent?
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detergent
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