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An antimicrobial chemical used on the skin is usually called a(n) __________. |
antiseptic Antiseptics often contain the same chemicals as disinfectants, but they are less concentrated and therefore safer to use on living tissues. |
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Which biosafety level requires that laboratory air be HEPA-filtered but is insufficient for the safe study Ebola? |
BSL-3 |
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Milk that can be stored for months at room temperature has been treated by which of the following methods? |
ultrahigh-temperature sterilization Ultrahigh-temperature sterilization kills all forms of living microbes: UHT-sterilized milk can be kept at room temperature indefinitely without spoilage, although flavor changes may occur. |
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Which of the following techniques can be used to sterilize microbiological media? |
autoclaving |
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A nurse preparing a section of skin for an injection is an example of __________. |
degerming Even something as simple as washing your hands can be an effective degerming method. |
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Which of the following is the preferred method of determining the efficacy of an antimicrobial chemical in the European Union? |
The Kelsey-Sykes capacity test is useful because it reveals the minimum amount of time required for a particular disinfectant to be effective. |
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Compared to moist heat methods, dry heat needs which of the following in order to sterilize effectively? |
higher temperature and increased time. Air does not conduct heat as effectively as water does, so sterilization methods that rely on hot air require more time and higher temperatures than methods involving moisture. |
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Which of the following is a low-level disinfectant? |
quats. Alcohols and halogens are both intermediate-level disinfectants, and oxidizing agents are considered to be high-level disinfectants. Quaternary ammonia compounds are less effective. |
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Hydrogen peroxide does NOT make a good antiseptic for open wounds because __________. |
catalase in human tissues neutralizes it. Human cells, like many other cells, contain protective enzymes such as catalase that are used to guard against the toxic byproducts of oxygen and its metabolism. |
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Damage to the cell wall will adversely affect a bacterial cell by making it more susceptible to __________. |
osmotic pressure. Without a strong, functional cell wall, the bacterial cell cannot resist sudden changes in osmotic pressure and can die as a result. |
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Put the following microbes in order of their resistance to antimicrobial agents, from least to most resistant: a. prions b. enveloped viruses c. mycobacteria d. Gram-negative bacteria |
enveloped viruses- Gram-negative bacteria- mycobacteria- prions |
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Hydrogen peroxide is an example of a(n) __________ and can serve as an effective disinfectant, though it does NOT work well as an antiseptic. |
oxidizing agent. |
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Iodophors and chloramines are similar in that they are both halogen-containing compounds that __________. |
slowly release their active ingredients. Iodophors and chloramines are so effective because they release their active ingredients more slowly than do the more elemental forms of these halogens. |
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Antimicrobial agents that damage the viral envelope __________. |
prevent attachment of the virus to its target cell. Viral envelopes allow the viruses to attach to cells so that they can replicate. |
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Which of the following is most susceptible to antimicrobial agents? |
Vegetative bacteria are active metabolically and will typically be more susceptible to antimicrobial control methods. |
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Which of the following is the most important part of sterilization using an autoclave? |
increased pressure. While all of these are important aspects of autoclaving as a sterilization procedure, it is the increased atmospheric pressure inside the autoclave that makes the increase in steam temperature possible. This increase in pressure also reduces the time needed for sterilization. |
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Which of the following could be used to sterilize objects such as medical devices? |
ethylene oxide |
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Which of the following could be used to sterilize a heat-sensitive liquid such as urea broth? |
filtration |
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A broth containing 1 million bacterial cells is treated with an antimicrobial agent that kills 90% of the cells in 1 minute. What is the minimum amount of time it will take before all the cells in the broth are dead? |
7 minutes. Because 90% of the cells present are killed each minute, the decline of the bacterial population gives a straight line when the experimental values are plotted on a semilogarithmic graph. The last cell will be killed at some point between 6 and 7 minutes of exposure. |
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An instrument coming into contact with the skin of an immunocompromised patient should be treated with which of the following? |
high-level germicide. An item that would need to be treated with only a low-level germicide in the case of a healthy patient would need to be sterilized with a high-level germicide if used with an immunocompromised patient. |
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Assume that you have an antimicrobial agent specific for each of the targets listed below. Indicate which type of microbe would be most susceptible to the agent by placing it in the appropriate bin. |
All bacteria- membrane proteins, glycolytic enzymes Gram-positive – peptidoglycan Viruses- envelope proteins All bacteria and viruses – nucleic acids |
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Which of the following shows the moist heat methods in order of the temperature used (highest to lowest)? |
Ultrahigh>Autoclave>Boiling>Batch Pasteurization |
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_______________ is a process used to destroy pathogens in food and drinks. It must be done at a lower temperature than other methods so that _______________. |
Pasteurization; the taste of the food or drink will not be altered |
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What are the 5 main antibacterial drug targets in bacteria? |
cell-wall synthesis metabolic enzymes DNA- directed RNA polymerase protein synthesis DNA gyrase |
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