Deck 11: Physical and Chemical Agents for Microbial Control

Question 1

The use of chemical agents directly on exposed body surfaces to destroy or inhibit vegetative pathogens is:

A)disinfection.
B)sterilization.
C)antisepsis.
D)sanitization.
E)degermation.

Answer 1

C

Question 2

Scrubbing or immersing the skin in chemicals to reduce the numbers of microbes on the skin is:

A)disinfection.
B)sterilization.
C)antisepsis.
D)sanitization.
E)degermation.

Answer 2

E

Question 3

The use of a physical or chemical process to destroy vegetative pathogens on inanimate objects is:

A)disinfection.
B)sterilization.
C)antisepsis.
D)sanitization.
E)degermation.

Answer 3

A

Question 4

The process that destroys or removes all microorganisms and microbial forms including bacterial endospores is:

A)disinfection.
B)sterilization.
C)antisepsis.
D)sanitization.
E)degermation.

Question 5

Endospores can be killed by:

A)dry heat at 170 ^$\circ$ C for 2 hours.
B)incineration.
C)glutaldehyde for 3 or more hours.
D)ethylene oxide for 3 or more hours.
E)All of the choices are correct.

Question 6

Physical agents for controlling microbial growth include all of the following, except:

A)ultraviolet radiation.
B)boiling water.
C)HEPA filters.
D)pasteurization.
E)hydrogen peroxide.

Question 7

Sterilization is achieved by:

A)flash pasteurization.
B)hot water.
C)boiling water.
D)steam autoclave.
E)All of the choices are correct.

Question 8

Electrons are ejected from atoms in cells when organisms are exposed to:

A)dessication.
B)ultraviolet light.
C)ethyl alcohol.
D)hydrogen peroxide.
E)gamma rays and X rays.

Question 9

Which of the following items are typically irradiated in order to kill microbes?

A)ground beef and other meat and poultry
B)human tissues such as heart valves and skin
C)operating room air
D)surgical gloves
E)All of the choices are correct.

Question 10

Disinfection of beverages, such as apple juice, milk, and wine, is optimally achieved by:

A)pasteurization.
B)chlorination.
C)moist heat autoclave.
D)filtration.
E)boiling water.

Question 11

The minimum sterilizing conditions in a steam autoclave are:

A)121 ^$\circ$ C at 15 psi for 15 minutes.
B)63 ^$\circ$ C for 30 minutes.
C)160 ^$\circ$ C for 2 hours.
D)71.6 ^$\circ$ C for 15 seconds.
E)100 ^$\circ$ C for 30 minutes.

Question 12

The process of using a cleansing technique to mechanically remove and reduce microorganisms and debris to safe levels is:

A)disinfection.
B)sterilization.
C)antisepsis.
D)sanitization.
E)degermation.

Question 13

Which is correct regarding the rate of microbial death?

A)cells die at increasingly greater rates
B)only older cells die in a culture
C)cells in a culture die at a constant rate
D)upon contact with the control agent, all cells die at one time
E)cells become metabolically inactive but are never killed

Question 14

Which of the following microbial forms have the highest resistance to physical and chemical controls?

A)naked viruses
B)protozoan cysts
C)fungal spores
D)bacterial endospores
E)yeast

Question 15

The shortest time required to kill all the microbes in a sample at a specified temperature is called the:

A)thermal death point (TDP).
B)thermal death time (TDT).
C)sporicidal time.
D)death phase point.
E)None of the choices are correct.

Question 16

Which of the following does not contain a heavy metal?

A)Tincture of iodine
B)Merthiolate
C)Silver nitrate solutions
D)Zinc
E)Mercurochrome

Question 17

Dry heat:

A)is less efficient than moist heat.
B)cannot sterilize.
C)includes tyndallization.
D)is used in devices called autoclaves.
E)will sterilize at 121 ^$\circ$ C for 15 minutes.

Question 18

HEPA filters are used to remove microbes from:

A)air.
B)liquids.
C)human tissues.
D)medical instruments.
E)All of the choices are correct.

Question 19

Which of the following types of control agents would be used to achieve sterility?

A)virucide
B)bactericide
C)germicide
D)sporicide
E)fungicide

Question 20

Microbiological contaminants are best described as:

A)unwanted microbes present on or in a substance.
B)any and all microbes present on or in a substance.
C)pathogenic microbes present on or in a substance.
D)vegetative microbes present on or in a substance.
E)None of the choices are correct.

Question 21

All the following are correct about detergents, except:

A)they are polar molecules that act as surfactants.
B)the most effective ones are positively charged.
C)in low concentrations they are bacteriostatic.
D)they are ineffective against the tuberculosis bacteria.
E)they are active in the presence of organic matter.

Question 22

All of the following are benefits of food irradiation, except:

A)it can kill bacterial pathogens on the food.
B)it can kill insects on the food.
C)it can inhibit the sprouting of white potatoes.
D)it can reduce the number of food-borne deaths each year.
E)it makes the food less nutritious.

Question 23

The easiest microbial forms to kill or inhibit are:

A)naked viruses.
B)vegetative bacteria and fungi.
C)endospores.
D)protozoan cysts.
E)Mycobacterium and Staphylococcus.

Question 24

The sterilizing gas used in a special chamber is:

A)ethylene oxide.
B)iodophor.
C)glutaraldehyde.
D)formaldehyde.
E)chlorine dioxide.

Question 25

Which of the following is officially accepted as a sterilant and high-level disinfectant?

A)benzalkonium chloride
B)silver nitrate
C)glutaraldehyde
D)triclosan
E)cresol

Question 26

All of the following are phenols or phenolics, except:

A)Lysol.
B)Hexachlorophene.
C)Triclosan.
D)Cresols.
E)Chloramines.

Question 27

All of the following pertain to hypochlorites, except:

A)release hypochlorous acid in solution.
B)cause denaturation of enzymes.
C)found in iodophors.
D)used to disinfect dairy, restaurant, and medical equipment.
E)found in common household bleach.

Question 28

The chemical agent that produces highly reactive hydroxyl-free radicals and also decomposes to O₂ gas is:

A)Cidex.
B)Cationic detergents.
C)Hydrogen peroxide.
D)Chlorhexidine.
E)Iodophors.

Question 29

The compound that is an organic base containing chlorine and two phenolic rings and is used increasingly for handscrubbing, neonatal washes, wound degerming, and prepping surgical skin sites is:

A)Carbolic acid.
B)Chlorhexidine.
C)Triclosan.
D)Formalin.
E)Quarternary ammonium compounds.

Question 30

Which is mismatched?

A)Sodium hypochlorite - chlorine
B)Iodophor - iodine
C)Benzalkonium chloride - quaternary ammonium compound
D)Merthiolate - silver
E)Formalin - formaldehyde

Question 31

Which of the following is being used to replace hypochlorites in treating water because of the possibility of cancer-causing substances being produced?

A)hydrogen peroxide
B)chloramines
C)fluorine
D)quaternary ammonium compounds
E)sodium iodide

Question 32

Alcohols:

A)denature proteins when in a 50-95% solution.
B)are used to disinfect items by soaking.
C)are skin degerming agents.
D)at 50% or higher concentrations dissolve cell membrane lipids.
E)All of the choices are correct.

Question 33

Which of the following chemicals is a disinfectant for soft contact lenses?

A)hydrogen peroxide
B)alcohol
C)hexachlorophene
D)glutaraldehyde
E)hypochorites

Question 34

All of the following are methods of disinfection or sterilization, except:

A)gamma radiation.
B)dry oven.
C)lyophilization.
D)triclosan.
E)ethanol.

Question 35

Which control method would not be a suitable choice for killing Mycobacteria in a capped culture tube?

A)ultraviolet (germicidal) light
B)gamma rays
C)121 ^$\circ$ C at 15 psi for 15 minutes
D)160 ^$\circ$ C for 2 hours
E)All of the choices are correct.

Question 36

Which of the following is not used as an antiseptic?

A)iodophor
B)chlorhexidine
C)3% hydrogen peroxide
D)Merthiolate
E)aqueous glutaraldehyde

Question 37

Iodophors include:

A)Chloramines.
B)Betadine.
C)Tincture of iodine.
D)Alcohols.
E)Chlorhexidine.

Question 38

All of the following are correct about iodophors, except:

A)they are complexes of iodine and a neutral polymer.
B)this formulation allows a quick release of free iodine.
C)this formulation increases its penetration.
D)it is less prone to staining or irritating tissue.
E)a common iodophor is Betadine.

Question 39

All of the following are correct about food irradiation, except:

A)food is not made radioactive by the process.
B)the World Health Organization does not endorse this process.
C)it is approved in the U.S.for beef, chicken, and pork.
D)it can lead to a longer shelf life for the irradiated food.
E)no irradiated food can be sold without clear labeling.

Question 40

Ethylene oxide is:

A)sporicidal.
B)only effective with high heat.
C)the active agent in household bleach.
D)used as an antiseptic against anaerobes.
E)a halogen.

Question 41

Alcohols are more effective at inactivating enveloped viruses than naked viruses.

Question 42

Using toilet bowl cleaner and nonionizing radiation to inanimate surfaces only removes or kills vegetative bacteria.The term that best describes this action is:

A)Sterilization
B)Disinfection
C)Antisepsis
D)Degermation
E)None of these are correct

Question 43

Most microbial contaminants of food are killed at freezing temperatures.

Question 44

Which common hospital pathogen is able to grow abundantly in soap dishes?

A)Escherichia coli
B)Pseudomonas
C)Hemophilus influenzae
D)Mycobacteria tuberculosis
E)Salmonella

Question 45

Bacteriocidal agents are sterilants.

Question 46

Aniline dyes like crystal violet have antimicrobial activity particularly against gram positive bacteria and some fungi.

Question 47

Filtration is an effective method to remove microbes from air and liquids.

Question 48

Bacteriostatic agents kill bacterial cells.

Question 49

Which of these metals have antimicrobial properties associated with them?

A)Silver
B)Gold
C)Tin
D)Aluminum
E)Both A and B are correct.

Question 50

Chlorine dioxide and ethylene oxide are gaseous sterilants.

Question 51

The presence of organic matter such as saliva and pus can interfere with the actions of disinfectants.

Question 52

Which of the following types of agents targets protein conformation?

A)Detergents
B)Ultraviolet light
C)Alcohol
D)Hydrogen peroxide
E)Crystal violet

Question 53

When a control agent targets the metabolic processes of microbial cells, active younger cells typically die more rapidly than older cells.

Question 54

Historically, which of the following was instilled into the eyes of newborn infants to prevent gonococcal infections?

A)triclosan
B)formaldehyde
C)phenol
D)silver nitrate
E)mercurochrome

Question 55

Commercial products containing which types of chemicals are more effective at killing microorganisms?

A)bacteriostatic
B)bacteriocidal
C)carbohydrate
D)lead
E)None of these are correct.

Question 56

Chlorine compounds remain stable and effective in the presence of excess organic matter.

Question 57

_____ heat is more rapidly effective and efficient compared to _____ heat.

Question 58

Isopropyl alcohol wiped across a skin site can sterilize it.

Question 59

A microorganism that is not motile and has stopped metabolizing could be considered dead.

Question 60

All of the following are correct about the autoclave, except:

A)it is important not to overload the chamber.
B)it is effective for sterilizing powders, oils, and waxy substances.
C)the duration of the process depends on how full the chamber is.
D)it is the temperature that kills the microbes, not the pressure by itself.
E)sterilization is achieved when steam condenses against the objects in the chamber and raises their temperatures.

Question 61

_____ radiation excites atoms to a higher energy state within molecules such as DNA that then leads to the formation of pyrimidine dimers.

Question 62

Compare and contrast antisepsis, disinfection, sanitization, and sterilization with regard to techniques used and level of microbial control achieved.

Question 63

A method for sterilizing milk, called _____ temperature treatment, uses 134 ^$\circ$ C for 1 to 2 seconds.

Question 64

Explain why boiling water is considered disinfection, not a sterilization method.List three materials commonly disinfected by boiling water.

Question 65

Discuss the advantages and disadvantages of irradiating food.Include examples of foods that are irradiated.

Question 66

_____ is a halogen used in gaseous and liquid form for large scale disinfection of drinking water and sewage.

Question 67

__________ or steam sterilization is the process by which steam is heated under pressure to sterilize objects.

Question 68

Vials of microorganisms that undergo the freeze-drying process called _____ will remain preserved and viable for years.

Question 69

Some microbial control agents are able to _____ cell proteins by breaking bonds that maintain the native state, three-dimensional configuration of the proteins.

Question 70

_____ filters are widely used to provide a flow of sterile air to hospital rooms.

Question 71

For each item listed below, select a sterilant that you feel is the most suitable and effective for that item.Discuss why you selected each sterilant.

A) plastic Petri dishes to be used for nutrient media
B) glass tubes of bacterial cultures to be discarded
C) sterile milk
D) dozens of reusable glass pipets
E) bone tissue for grafting
F) room air
G) hospital mattresses
H) biopsy tissue for histology analysis
I) plastic respiratory therapy equipment and arthroscopes
J) vaccines

Question 72

Discuss the purpose and level of control achieved by pasteurization.Compare the flash and batch methods.

Question 73

Discuss the technique of filtration as a microbial control method, why it's utilized, and specific materials that are filtered.