Physical And Chemical Control Ch9 Test Questions & Answers

Microbiology Fundamentals: A Clinical Approach, 3e (Cowan)

Chapter 9 Physical and Chemical Control of Microbes

1) 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

2) The process that destroys or removes all microorganisms and microbial forms including bacterial endospores on inanimate objects is ________.

A) disinfection

B) sterilization

C) antisepsis

D) sanitization

E) degermation

3) 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

4) The use of a physical or chemical process to destroy vegetative pathogens is ________.

A) disinfection

B) sterilization

C) antisepsis

D) sanitization

E) degermation

5) 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) ionization

6) 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) ionization

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

A) Virucide

B) Bactericide

C) Germicide

D) Sporicide

E) Fungicide

8) The easiest microbial forms to kill or inhibit are ________.

A) prions

B) vegetative bacteria and fungi

C) endospores

D) protozoan cysts

E) mycobacteria and staphylococci

9) The method of removing vegetative microbial life forms from inanimate objects is termed ________.

A) antisepsis

B) disinfection

C) sterilization

D) decontamination

E) degerming

10) The method of removing vegetative life forms from living surfaces is termed ________.

A) antisepsis

B) disinfection

C) sterilization

D) decontamination

E) degerming

11) The removal of all life forms from inanimate objects is termed ________.

A) antisepsis

B) disinfection

C) sterilization

D) decontamination

E) degerming

12) The betadine swab before blood donation is an example of ________.

A) antisepsis

B) disinfection

C) sterilization

D) decontamination

E) sanitation

13) The alcohol wipe before an injection is an example of ________.

A) antisepsis

B) disinfection

C) sterilization

D) decontamination

E) virilization

14) A cleansing method that mechanically removes microbes and other debris to reduce contamination is ________.

A) disinfection

B) sterilization.

C) antisepsis

D) sanitization

E) degermation

15) 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.

16) Which of the following factors will influence the action of antimicrobial agents?

A) The number of microorganisms

B) The kind of microorganisms

C) Temperature and pH

D) Mode and dosage of the agent

E) All of these will influence the action.

17) Microbial death occurs when there is ________.

A) no movement

B) permanent loss of reproduction

C) a change in appearance

D) a decrease in size

E) All of these occur

18) Each of the following is the target of antimicrobial agents except ________.

A) cell walls

B) cell membranes

C) ribosomes

D) cellular proteins

E) cytoplasm

19) Surfactants work by ________.

A) coating the organism, preventing interaction with its environment

B) blocking transport into the organism

C) blocking transport out from the organism

D) disrupting membrane integrity

E) All of the choices are correct

20) Some microbial control agents are able to ________ cell proteins by breaking bonds that maintain the native state (three-dimensional configuration) of the proteins.

A) denature

B) bind

C) dissolve

D) activate

E) All of the choices are correct.

21) Agents that can denature microbial proteins include all of the following except ________.

A) moist heat

B) alcohol

C) acids

D) metallic ions

E) X rays

22) Which of the following does not affect microbial nucleic acids?

A) Moist heat

B) Ultraviolet light

C) X rays

D) Ethylene dioxide

E) Formaldehyde

23) Physical agents for controlling microbial growth include all the following except ________.

A) ultraviolet radiation

B) boiling water

C) HEPA filters

D) pasteurization

E) hydrogen peroxide

24) Sterilization is achieved by ________.

A) flash pasteurization

B) hot water

C) boiling water

D) steam autoclave

E) All of the choices are correct

25) 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°C for 15 minutes

26) The most efficient sterilizing conditions in a steam autoclave are ________.

A) 121°C at 15 psi for 15 minutes

B) 63°C for 30 minutes

C) 160°C for 2 hours

D) 71.6°C for 15 seconds

E) 100°C for 30 minutes

27) 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

28) The lowest temperature needed to kill all microbes in 10 minutes is 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

29) Disinfection of beverages such as apple juice, milk, wine is optimally achieved by ________.

A) pasteurization

B) chlorination

C) moist heat autoclave

D) hydrogen peroxide

E) boiling water

30) Placing organisms at 4oC is ________.

A) bactericidal

B) bacteristatic

C) decontamination

D) sterilization

E) None of the choices are correct

31) Pasteurization ________.

A) kills all vegetative forms

B) reduces the number of vegetative forms

C) reduces the number of endospores

D) increases food nutrient value

E) None of the choices are correct

32) ________ heat is more rapidly effective and efficient compared to ________ heat.

A) High; dry

B) High; moist

C) Dry; moist

D) Moist; dry

E) Moist; high

33) A method for sterilizing milk, called ________ treatment, uses 134°C for 1 to 2 seconds.

A) pasteurization

B) batch pasteurization

C) flash pasteurization

D) ultra high temperature

E) None of the choices are correct

34) What instrument is most effective for pressure-temperature sterilization?

A) Oven

B) Autoclave

C) Water bath

D) Bunsen burner

E) Incubator

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

A) desiccation

B) flash freeze

C) lyophilization

D) pasteurization

E) sterilization

36) Removal of moisture by dehydration is called ________.

A) desiccation

B) flash freeze

C) lyophilization

D) pasteurization

E) sterilization

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

A) Infrared

B) Ultraviolet

C) Gamma

D) Particle

E) Ionizing

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

A) Meats like ground beef and pork

B) Human tissues such as heart valves and skin

C) Operating room air

D) Surgical gloves

E) All of the choices are correct.

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

A) Ultraviolet (germicidal) light

B) Gamma rays

C) 121°C at 15 psi for 15 minutes

D) 160°C for 2 hours

E) All of the choices would kill Mycobacterium in a culture tube.

40) Which of the following forms of radiation is in order from the most penetrating to the least penetrating?

A) Gamma, cathode, X rays

B) Gamma, X rays, cathode

C) Cathode, gamma, X ray

D) Cathode, X ray, gamma

E) X ray, gamma, cathode

41) 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

42) ________ is a control method that removes microorganisms rather than inhibiting or killing them.

A) Boiling

B) Sterilization

C) Radiation

D) Filtration

E) Disinfection

43) Which of the following is not a factor that affects germicidal activity?

A) The material being treated

B) The length of exposure

C) The strength of the germicide

D) The microorganism being treated

E) All of these choices are factors.

44) 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 water, restaurant, and medical equipment

E) found in common household bleach

45) ________ is a halogen used in gaseous and liquid form for large-scale disinfection of drinking water and sewage.

A) Iodine

B) Chlorine

C) Bromine

D) Fluorine

E) All of the choices are correct.

46) The compound that is an organic base containing chlorine and two phenolic rings, and is used increasingly for mucous membrane irrigation, obstetrical washes, hand scrubbing, and prepping surgical skin sites is ________.

A) carbolic acid

B) chlorhexidine

C) triclosan.

D) formalin

E) quarternary ammonium compounds

47) Alcohols ________.

A) dissolve membrane lipids at concentrations of greater than 50%

B) can be used for disinfection or antisepsis

C) are skin degerming agents

D) are limited in effectiveness due to rapid evaporation

E) All of the choices are correct

48) The chemical agent that produces highly toxic and reactive free radicals is ________.

A) cidex

B) cationic detergents

C) hydrogen peroxide

D) chlorhexidine

E) iodophors

49) Hydrogen peroxide can be ________.

A) sporicidal

B) fungicidal

C) bactericidal

D) virucidal

E) All of the choices are correct

50) All of the following disrupt the cytoplasmic membrane except ________.

A) detergents

B) quaternary ammonium compounds

C) high concentration phenols

D) iodine

51) Heavy metals work by ________.

A) rupturing the cell membrane

B) inactivating proteins

C) binding to DNA

D) dissolving the cell wall

E) mutating DNA

52) Which of the following is not used as an antiseptic?

A) Iodophor

B) Chlorhexidine

C) 3% hydrogen peroxide

D) Betadine (povidone-iodine)

E) Glutaraldehyde

53) 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

54) Which of the following acids is not used to destroy or inhibit microbial cells in food?

A) Acetic acid

B) Benzoic acid

C) Lactic acid

D) Phosphoric acid

E) Propionic acid

55) In lab, inoculating loops are sterilized using ________.

A) moist heat

B) chemicals

C) incineration

D) filtration

E) ethylene oxide

56) Antimicrobial agents can target the cell wall by ________.

A) blocking its synthesis

B) digesting it

C) inhibiting peptidoglycan synthesis

D) All of the choices are correct

57) Which of the following represents the use of osmotic pressure as a microbial control method?

A) Bleaching a kitchen counter

B) Salting meat

C) Rinsing a cut with Betadine

D) Both bleaching a kitchen counter and rinsing a cut with Betadine are correct.

58) Microbicidal agents are sterilants.

59) Bacteristatic agents kill bacterial cells.

60) Prions require more extensive methods of sterilization than are needed for bacterial endospores.

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

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

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

64) Most microbial contaminants of food are killed at freezing temperatures.

65) Pasteurization will make milk sterile.

66) Pasteurization does not kill endospores or thermoduric microbes.

67) Ionizing radiation is more effective than nonionizing radiation in killing microbes.

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

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

70) Isopropyl alcohol wiped across a skin site can sterilize it.

71) Hydrogen peroxide can be used to sterilize instruments such as endoscopes.

72) Soaps and detergents are very effective as sterilants.

73) Pseudomonas is resistant to soaps.

74) Ethylene oxide is a sterilizing gas.

75) Analine dyes, like crystal violet, have antimicrobial activity particularly against gram-positive bacteria and some fungi.

76) Which pair of physical control methods will achieve complete sterilization?

A) Autoclaving and ionizing radiation

B) Ultraviolet radiation and filtration

C) Freezing and filtration

D) Osmotic pressure and incineration

E) Pasteurization and ultraviolet radiation

77) Of the six methods of controlling growth by physical means; heat, cold, desiccation, radiation, filtration and osmotic pressure, the only method that is capable of complete sterilization is radiation.

78) Which of the following statements is true when comparing moist heat methods of microbial control to dry heat control?

A) Both moist heat and dry heat methods can achieve complete sterilization.

B) Only moist heat (autoclaving) can sterilize objects, dry heat is limited to disinfection.

C) Dry heat is more efficient than moist heat, requiring less time to sterilize objects.

D) Boiling is a more successful method of sterilizing instruments than using a dry heat oven.

79) Temperature and time must be considered when determining susceptibility of microbes to lethal conditions.  At a specific temperature, the thermal death ________ can be determined, alternatively, the thermal death ________ can be assessed as the lowest temperature that will kill a test organism in 10 minutes.

A) time; point

B) point; time

C) exposure, time

D) point; exposure

80) All of the following are accurate statements concerning microbial control using dry heat except ________.

A) it is the preferred method of control to sterilize cottons, plastics and paper

B) it takes up to 4 hours to sterilize instruments in a hot-air oven, whereas the Bunsen burner will incinerate an inoculating loop almost immediately

C) the Bunsen burner can achieve temperatures up to 1,870oC, whereas the hot-air oven reaches temperatures of up to 180oC

D) while fast and effective, the Bunsen burner is limited to metals and glassware, whereas powders and oils can also be sterilized in the hot-air oven

81) When comparing the Bunsen burner and a hot-air oven, the Bunsen burner is more versatile since it can sterilize a wide range of materials, including plastics, cottons and oils.

82) Beginning Fall 2017, the FDA banned the use of phenolic compounds, such as triclosan, in consumer soaps and lotions.  This is due to ________.

A) increased microbial resistance to these chemicals

B) they only work against bacterial cells, not fungi or viruses

C) the inefficiency of phenolics as antimicrobials

D) a worldwide shortage of triclosan

83) Phenols are useful antimicrobial compounds in that they are effective against bacteria fungi and viruses, disrupting several cellular targets, however, they have been removed from many consumer products because of their high toxicity and propensity to select for resistant strains of microorganisms.

84) Chlorhexidine kills microbes by ________.

A) targeting cell membranes, cell walls and denaturing proteins

B) disrupting cell surface tension

C) inactivating enzymes by binding to the active site

D) blocking DNA replication

E) forming free radicals that create thymine dimers in the DNA

85) Heavy metals such as silver, mercury and copper are effective antimicrobials due to their ability to bind to the regulatory site of enzymes, thus acting as an irreversible non-competitive inhibitor.

86) All of the following are disadvantages to using compounds containing heavy metals, except ________.

A) they can only be taken in pill form, not applied as a lotion or ointment

B) they may cause allergic reactions in susceptible individuals

C) organisms can develop resistance to the compounds

D) they are not effective against endospores

E) they can be toxic

87) The use of aldehydes as antimicrobial agents is limited due to ________.

A) their instability when pH or temperature is increased

B) their explosive nature

C) they will disinfect, but not sterilize

D) they are ineffective in the presence of organic matter

88) One disadvantage to using ortho-phthalaldehyde vs. glutaraldehyde as an antimicrobial agent is ________.

A) increased cost

B) decreased efficacy

C) decreased safety

D) increased toxicity

89) Aldehyde-based compounds, while effective sterilants, can be unstable and costly to use.

90) The advantage of using ethylene oxide as a sterilant over moist heat sterilization in an autoclave is that ________.

A) it kills endospores, whereas the autoclave will only kill vegetative cells

B) it is much safer for humans to work with ethylene oxide than to operate an autoclave

C) it can be used to sterilize plastics that would melt in an autoclave

D) All of the choices are reasons to preferentially use ethylene oxide as a sterilant

NCLEX Prep - Test Bank Question:  Please read the clinical scenario, and then answer the questions that follow to become familiar with the traditional NCLEX question format.

An RN in a long-term care facility oversees the care of 15 patients. He observes precautions to control and prevent the spread of infection.

91) The RN practices proper handwashing technique when his hands are visibly dirty. Which of the following terms most appropriately describes the type of antimicrobial control provided by handwashing with germicidal soap and water?  

A) Sterilization

B) Disinfection

C) Decontamination

D) Antisepsis

92) The RN utilizes an alcohol-based hand cleanser with friction rub when his hands are not visibly dirty. Which of the following terms appropriately describes the type of antimicrobial control provided by alcohol-based hand cleansers?  

A) Sterilization

B) Disinfection

C) Decontamination

D) Antisepsis

93) Which of the following scenarios are most appropriate for handwashing with an alcohol-based hand cleanser instead of soap and water?  

A) Following a diaper change with visible soiling on the hands after glove removal

B) Following a wound dressing change when a glove tore during the procedure

C) Prior to applying gloves

D) Prior to returning to work after eating lunch

94) Which of the following microbes are targeted by alcohol-based hand cleaners?  

A) Bacteria

B) Viruses

C) Fungi

D) Bacteria, viruses, and fungi

NCLEX Prep - Test Bank Question:  Please read the clinical scenario, and then answer the questions that follow to become familiar with the traditional NCLEX question format.

A 13-year-old male is admitted to the pediatric intensive care unit. The patient has a history of mental retardation and cerebral palsy following an anoxic injury as an infant. The patient was admitted two months earlier due to aspiration pneumonia, necessitating a lengthy hospital stay, mechanical ventilation, and intravenous antibiotics. His caregiver reports another aspiration event two days prior. For the past 24 hours, the patient has been lethargic with a frequent cough producing thick sputum. Upon presentation to the hospital, the patient is noted to have a fever, low oxygen saturations, and low blood pressure. Upon arrival to the intensive care unit, the patient is cool, pale, and has poor pulses and capillary refill. Following administration of intravenous fluid boluses, it is determined the patient needs central venous access for fluid and medication administration. The RN prepares for the sterile procedure.

95) To reduce the patient's risk of infection, the RN assists the physician with applying all of the following prior to the procedure except ________.

A) sterile gloves

B) clean gown

C) cap

D) mask

96) Prior to placement of the central venous line, the patient's skin is scrubbed with chlorhexidine. Which of the following microorganisms are targeted by this chemical agent?  

A) Bacteria

B) Viruses

C) Fungi

D) Bacteria, viruses, and fungi

97) If chlorhexidine is unavailable for the procedure, which of the following chemical agents would also be appropriate as a topical antiseptic?  

A) 2% iodine

B) 10% potassium iodide

C) Formaldehyde

D) Phenol

98) Following successful placement of the central venous line, the RN is diligent to prevent infection when accessing the catheter and administering medications. Which of the following actions should be completed prior to use of the line?  

A) Hand washing

B) Disinfection of the access port with alcohol prior to use

C) Application of gloves

D) Hand washing, application of gloves, and disinfection of the access port with alcohol should all be completed prior to use of the line.

NCLEX Prep - Test Bank Question:  Please read the clinical scenario, and then answer the questions that follow to become familiar with the traditional NCLEX question format.

A woman who is 38 weeks pregnant is admitted for a scheduled cesarean section. The RN performs an assessment of the patient and prepares her for the surgery. Prior to the procedure, an indwelling urinary catheter is placed.

99) The RN prepares the patient for the sterile procedure. Which of the following statements made by the patient, best demonstrates understanding of the need for sterile equipment and aseptic procedures?  

A) Sterile equipment and aseptic procedures are utilized so there are no microorganisms introduced that could cause infection.

B) Sterile equipment and aseptic procedures are utilized to reduce trauma to the urinary tract.

C) Sterile equipment and aseptic procedures are utilized to protect the nurse from infection.

D) Sterile equipment and aseptic procedures are utilized so that microorganisms on the skin that could cause infection are destroyed.

100) The RN cleanses the urethral opening with an iodine swab. Which of the following terms most appropriately describes this method of microbial control?  

A) Disinfection

B) Antisepsis

C) Decontamination

D) Sterilization

101) After preparing the patient's skin, the RN brushes against the sterile field with her arm. What is the most appropriate action by the RN? 

A) Continue the procedure and place the catheter.

B) Clean the catheter with alcohol, and then continue the procedure.

C) Discard the sterile field and obtain new supplies.

D) Clean the catheter with iodine, and then continue the procedure.