Chapter 11 Practice Exercises Flashcards
Sanitization is a process by which
Multiple Choice
A) objects are made sterile with chemicals.
B) the microbial load on an object is reduced.
C) skin is debrided.
D) hands are scrubbed.
B) the microbial load on an object is reduced.
Select the major cellular targets of physical and chemical control agents.
Check All That Apply
A) Cell wall
B) Flagella
C) Cell membrane
D) Proteins
E) Microcompartments
A) Cell wall
C) Cell membrane
D) Proteins
Explanation: There are four main targets of physical and chemical control agents. These include the cell wall, the cell membrane, cellular synthetic processes, and proteins.
Disinfection procedures must take into account
Multiple Choice
A) the mixture of microbes being targeted.
B) whether the microbes in biofilms are dispersed.
C) the amount of organic matter associated with the microbes.
D) All of these choices must be taken into account.
D) All of these choices must be taken into account.
Select the characteristics of a chemical control agent that make it a desirable agent.
Check All That Apply
A) Corrosive to metals and plastics
B) Water or alcohol soluble and stable
C) “-cidal” to a wide range of microbes, but nontoxic to humans and animal tissue
D) Rapidly effective in low concentrations
E) Ineffective in the presence of organic matter
F) Inexpensive
G) Short-lived, spontaneously inactivates with time
B) Water or alcohol soluble and stable
C) “-cidal” to a wide range of microbes, but nontoxic to humans and animal tissue
D) Rapidly effective in low concentrations
F) Inexpensive
Explanation: Some desirable characteristics that chemical control agents should possess include the following: They should be rapidly effective in low concentrations, -cidal to a wide range of microbes yet nontoxic to human and animal tissue, soluble in water or alcohol, inexpensive, noncorrosive to metals and plastics, demonstrate persistent or cumulative activity, and be stable and effective in the presence of organic matter.
Because prions are so resistant to typical control methods, it is not important to consider them when attempting to sterilize a substance or environment.
A) True
B) False
B) False
Explanation: Sterilization means void of all microbial life. Prions are merely infectious protein molecules, but they are important agents of disease that must be considered when sterilizing items such as surgical instruments.
Clostridioides difficile forms endospores. This characteristic makes this pathogen a concern for healthcare-associated infections.
A) True
B) False
A) True
Explanation: Endospores are highly resistant, making any organism that produces them highly resistant. This has made C. diff a major cause of HAIs (healthcare-association infections).
Order these types of microbes in terms of their resistance, from least resistance to most resistance.
A) Enveloped viruses, naked viruses, vegetative bacteria, protozoans, endospores, prions
B) Naked viruses, enveloped viruses, vegetative bacteria, protozoans, endospores, prions
C) Enveloped viruses, naked viruses, protozoans, vegetative bacteria, endospores, prions
D) Enveloped viruses, naked viruses, protozoans, prions, vegetative bacteria, endospores
A) Enveloped viruses, naked viruses, vegetative bacteria, protozoans, endospores, prions
Explanation: Review Figure 11.2 to help you determine the relative resistance of different microbial agents.
Which of these represents a chemical sterilant?
A) Chlorhexidine
B) Phenolics
C) Alcohols
D) Ethylene oxide
D) Ethylene oxide
Explanation: Ethylene oxide is a chemical sterilant. The others only affect some microbes and are not sporocidal.
Select all of the food items where microbial growth is controlled by means of osmotic pressure.
Check All That Apply
A) Honey
B) Apple cider
C) Salt-cured meats
D) Milk
E) Yogurt
F) Jellies
A) Honey
C) Salt-cured meats
F) Jellies
Explanation: Some foods are preserved by osmotic pressure. This is done by creating a hypertonic environment with salt or sugar that will cause bacteria to plasmolyze. Examples are honey, corn syrup, and jellies (high sugar) as well as salt-cured meats and fish (high salt).
Desiccation is a form of physical control of microorganisms that can be used in moist or dry forms.
A) True
B) False
B) False
Explanation: The six methods of physical control of microorganisms include heat (which can occur in moist or dry forms), cold, radiation, filtration, desiccation, and osmotic pressure. Desiccation refers to “drying” so there is definitely not a moist option!
Select the advantages of glutaraldehyde as an antimicrobial agent.
Check All That Apply
A) It can be used as an antiseptic as well as a disinfectant.
B) It remains effective in the presence of organic matter.
C) It is non-corrosive.
D) It is a chemical sterilant and high level disinfectant.
E) It is effective over a broad range of pH and temperatures.
B) It remains effective in the presence of organic matter.
C) It is non-corrosive.
D) It is a chemical sterilant and high level disinfectant.
Explanation: Glutaraldehyde is a broad-spectrum microbicide that is classified as a chemical sterilant and high level disinfectant. It maintains its activity in the presence of organic matter, is non-corrosive, and does not damage plastics. While less toxic than formaldehyde (another adehyde used for microbial control), it is not used as an antiseptic. The major disadvantage is its instability at increased pH and temperature.
The most versatile method for sterilizing heat-sensitive liquids is
Multiple Choice
A) peracetic acid.
B) exposure to ozone.
C) UV radiation.
D) filtration.
D) filtration.
Transcription is targeted most directly by
Multiple Choice
A) detergents.
B) quats.
C) alcohol.
D) UV radiation.
D) UV radiation.
Match the term to its description to test your understanding of the use of moist heat methods to control microbial growth.
1) Steam under pressure 2) Pasteurization
3) Boiling water
A) This method requires the use of an autoclave. To sterilize, temperature must reach 121°C for a minimum of 15 minutes.
B) Heat is applied to beverages to prevent spoilage and kill pathogens, but it does not sterilize. Protocols include holding liquids at 71.6°C for 15 seconds or at 63°C for 30 minutes.
C) This exposes a material to a temperature of 100°C. Thirty minutes of exposure will disinfect but will not sterilize.
1) Steam under pressure
A) This method requires the use of an autoclave. To sterilize, temperature must reach 121°C for a minimum of 15 minutes.
2) Pasteurization
B) Heat is applied to beverages to prevent spoilage and kill pathogens, but it does not sterilize. Protocols include holding liquids at 71.6°C for 15 seconds or at 63°C for 30 minutes.
3) Boiling water
C) This exposes a material to a temperature of 100°C. Thirty minutes of exposure will disinfect but will not sterilize.
Evaluate the statements below, and select those that correctly apply to the use of radiation as a microbial control mechanism.
Check All That Apply
A) The use of radiation to control microbial growth comes in two forms; ionizing and nonionizing radiation. Of the two, ionizing radiation is the most destructive.
B) Nonionizing radiation involves electrons being bombarded with enough energy to eject them from their atoms. Gamma rays are an example of this.
C) Nonionizing radiation, e.g., UV light, causes electrons to make a quantum leap to an orbital with a higher energy state, which causes thymine dimers to form, but does not create ions.
D) Ionizing radiation involves electrons being bombarded with enough energy to eject them from their atoms. X rays are an example of this.
E) The use of radiation to control microbial growth comes in two forms; ionizing and nonionizing radiation. Of the two, nonionizing radiation is the most destructive.
A) The use of radiation to control microbial growth comes in two forms; ionizing and nonionizing radiation. Of the two, ionizing radiation is the most destructive.
C) Nonionizing radiation, e.g., UV light, causes electrons to make a quantum leap to an orbital with a higher energy state, which causes thymine dimers to form, but does not create ions.
D) Ionizing radiation involves electrons being bombarded with enough energy to eject them from their atoms. X rays are an example of this.
What was the most likely mode of transmission of Cryptosporidium at the Seneca Lake State Park Sprayground?
A) Via a vector
B) Airborne
C) Water-borne
D) Food-borne
C) Water-borne
Explanation: The outbreak was most likely water-borne, where transmission of the pathogen to the children occurred through ingesting water from the spray fountains as they played.
Cryptosporidium was able to evade or resist filtration and chlorination of the spray park’s water supply.
A) True
B) False
A) True
Explanation: Cryptosporidium is resistant to chlorine and is small enough to pass through filters, and therefore was able to evade the spray park’s water treatment systems.
