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full file at http://testbankcorner.euExam

Name___________________________________

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

1) Alcohols are used for 1)A) antisepsis.B) sterilization.C) disinfection.D) both sterilization and disinfection.E) both antisepsis and disinfection.

Answer: EExplanation: A)

B)C)D)E)

2) Which of the following infectious agents is least resistant to destruction by chemical methods? 2)A) enveloped virusesB) fungal sporesC) nonenveloped virusesD) vegetative bacterial cellsE) bacterial endospores

Answer: AExplanation: A)

B)C)D)E)

3) Which of the following is used for microbial control in fresh fruits and vegetables? 3)A) gamma raysB) ultraviolet lightC) microwavesD) electron beamsE) X-rays


B)C)D)E)

1

full file at http://testbankcorner.eu4) Which of the following was used in the past to prevent the transmission of gonorrhea from an

infected mother to her newborn?4)

A) silver nitrateB) hydrogen peroxideC) beta-propiolactoneD) hexachloropheneE) thimerosal


B)C)D)E)

5) Which of the following statements is TRUE of disinfectants? 5)A) They are only effective for short periods of time (seconds to minutes).B) They are effective in destroying endospores.C) They are used on inanimate surfaces.D) They are used on living tissue.E) They are used for sterilization.

Answer: CExplanation: A)

B)C)D)E)

6) An instrument that will come into contact with only the skin of a patient should be disinfected witha(n)

6)

A) degerming agent only.B) low-level germicide.C) germistatic agent only.D) intermediate-level germicide.E) high-level germicide.

Answer: BExplanation: A)

B)C)D)E)

2

full file at http://testbankcorner.eu7) Which of the following statements about quaternary ammonium compounds is FALSE? 7)

A) They are harmless to humans except at high concentrations.B) They function by cross-linking proteins.C) They are a type of detergent.D) Zephiran is an example of a quat.E) They are not effective against Pseudomonas aeruginosa.


B)C)D)E)

8) Which of the following is a target of pasteurization? 8)A) Brucella melitensisB) Neisseria gonorrhoeaeC) Chlamydia trachomatisD) Bacillus stearothermophilusE) Clostridium botulinum


B)C)D)E)

9) Gamma irradiation is a process for 9)A) sterilization.B) antisepsis.C) degerming.D) disinfection.E) both antisepsis and disinfection.


B)C)D)E)

10) Which of the following statements about aldehydes is FALSE? 10)A) They denature proteins.B) They are usually hazardous to humans.C) Some aldehydes can sterilize after long periods of exposure.D) They are used only to preserve dead tissues.E) They are used in aqueous solutions.

Answer: DExplanation: A)

B)C)D)E)

3

full file at http://testbankcorner.eu11) Which of the following is a sterilizing agent? 11)

A) peracetic acidB) ozone and hydrogen peroxideC) hydrogen peroxideD) ozoneE) dish soap


B)C)D)E)

12) Which of the following types of radiation is nonionizing and has the shortest wavelength? 12)A) gamma raysB) ultraviolet lightC) infrared radiationD) X-raysE) microwaves


B)C)D)E)

13) Which of the following describes flash pasteurization? 13)A) heating at 72°C for 15 minutesB) heating at 72°C for 15 secondsC) heating at 134°C for one secondD) passing liquid through steam at 140°CE) heating at 63°C for 30 minutes


B)C)D)E)

14) Glutaraldehyde is used for 14)A) sterilizationB) sanitization.C) disinfection.D) antisepsis.E) both disinfection and sterilization.


B)C)D)E)

4

full file at http://testbankcorner.eu15) The process of filtration is a(n) 15)

A) disinfectant method.B) ineffective method for removing microbes.C) sanitization method.D) sterilizing method.E) antiseptic procedure.


B)C)D)E)

16) The endospores of which of the following microbes are used to measure the effectiveness ofautoclave sterilization?

16)

A) Mycobacterium bovisB) Clostridium botulinumC) Bacillus stearothermophilusD) Pseudomonas aeruginosaE) Neisseria gonorrhoeae


B)C)D)E)

17) Which of the following would be used to sterilize a mattress? 17)A) heavy metalsB) ethylene oxideC) formaldehydeD) radiationE) autoclaving


B)C)D)E)

18) Which of the following is NOT a feature associated with filtration? 18)A) use of HEPA filters to filter airB) ability of some filters to trap viruses and proteinsC) nitrocellulose or plastic membrane filtersD) sterilization of heat-sensitive materialsE) varying thicknesses of membrane filters used


B)C)D)E)

5

full file at http://testbankcorner.eu19) Disinfecting agents naturally produced by microorganisms are 19)

A) aldehydes.B) triclosans.C) quats.D) halogens.E) antimicrobials.


B)C)D)E)

20) Boiling water for 10 minutes is effective in ridding it of 20)A) protozoan cysts.B) enveloped viruses.C) actively growing bacteria.D) bacterial endospores.E) both growing bacteria and enveloped viruses.


B)C)D)E)

21) Which of the following can be used to disinfect air? 21)A) HEPA filtersB) ultraviolet lightC) ethylene oxideD) both HEPA filters and ultraviolet lightE) both ethylene oxide and ultraviolet light


B)C)D)E)

6

full file at http://testbankcorner.eu22) A stationary broth culture contains 10 billion (1010) cells. The microbial death rate during

autoclaving of this spent culture is 1.5 minutes. How long must it be autoclaved to be consideredsterile?

22)

A) 10 minutesB) 9 minutesC) 12 minutesD) 16.5 minutesE) 20 minutes


B)C)D)E)

23) Which of the following is the most difficult to inactivate? 23)A) fungus sporesB) bacterial endosporesC) protozoal cystsD) nonenveloped virusesE) enveloped viruses


B)C)D)E)

24) ________ is the physical removal of microbes. 24)A) AntisepsisB) SanitizationC) DisinfectionD) SterilizationE) Degerming


B)C)D)E)

7

full file at http://testbankcorner.eu25) Antimicrobial agents that damage nucleic acids also affect 25)

A) the cell membrane.B) the cell wall.C) protein synthesis.D) endospores.E) the viral envelope.


B)C)D)E)

26) ________ may be achieved using chlorine dioxide. 26)A) SterilizationB) DegermingC) AntisepsisD) DisinfectionE) Both antisepsis and degerming


B)C)D)E)

27) A scientist develops a new medication that is a protein compound and that must be administeredby injection. Which of the following would be the most effective and safest means of preparing asterile solution of the new medication?

27)

A) filtrationB) autoclavingC) dilution with alcoholD) ultraviolet irradiationE) lyophilization


B)C)D)E)

8

full file at http://testbankcorner.eu28) Which of the following is used to sterilize items that should not, or cannot, be exposed to heat or

water?28)

A) hydrogen peroxideB) ethylene oxideC) calcium hypochloriteD) triclosanE) formaldehyde


B)C)D)E)

29) Silvadene, a topical treatment for burns, contains 1% silver. What category of chemical controlagent is in Silvadene?

29)

A) halogensB) aldehydesC) oxidizing agentsD) heavy metalsE) surfactants


B)C)D)E)

30) The chemical agents known as "quats" are used for 30)A) sterilization.B) quantifying antimicrobial activity.C) neither antisepsis nor disinfection.D) disinfection.E) antisepsis.


B)C)D)E)

9

full file at http://testbankcorner.eu31) The use of lysozyme during the preparation of cheeses and wines is effective in reducing the

numbers of31)

A) all microbes.B) bacteria.C) fungi.D) viruses.E) prions.


B)C)D)E)

32) A chemical agent that kills pathogenic microbes in general is a(n) 32)A) disinfectant.B) antiseptic.C) fungicide.D) germicide.E) sanitizer.


B)C)D)E)

33) Which of the following antimicrobial agents is the most toxic to humans? 33)A) 70% alcoholB) ethylene oxideC) iodophorsD) chloraminesE) quats


B)C)D)E)

34) The compound ethylene oxide is used in 34)A) sanitization.B) disinfection.C) sterilization.D) degerming.E) antisepsis.


B)C)D)E)

10

full file at http://testbankcorner.eu35) Aseptic means 35)

A) free of all microbes.B) clean.C) free of pathogens.D) sanitized.E) sterile.


B)C)D)E)

36) The process of incineration is used for 36)A) degerming.B) sanitization.C) disinfection.D) sterilization.E) both disinfection and sanitization.


B)C)D)E)

37) Which of the following is an example of sanitization? 37)A) An autoclave is used to prepare nutrient agar.B) A public toilet is treated with disinfectants.C) A nurse prepares an injection site with an alcohol swab.D) A surgeon washes her hands before surgery.E) Heat is used to kill potential pathogens in apple juice.


B)C)D)E)

38) The dairy creamer used in restaurants is usually treated by 38)A) lyophilization.B) autoclaving.C) ultra-high-temperature pasteurization.D) filtration.E) ionizing radiation.


B)C)D)E)

11

full file at http://testbankcorner.eu39) Which of the following procedures is currently the standard test used in the United States for

evaluating the efficiency of antiseptics and disinfectants?39)

A) use-dilution testB) phenol coefficientC) in-use testD) microbial death rateE) thermal death point


B)C)D)E)

40) Which of the following is the most appropriate pairing of microbe and biosafety level? 40)A) tuberculosis, BSL-1B) E. coli, BSL-3C) methicillin-resistant Staphylococcus aureus (MRSA), BSL-2D) anthrax, BSL-1E) Ebola, BSL-2


B)C)D)E)

41) Which of the following is bacteriostatic? 41)A) flash PasteurizationB) filtrationC) heating in an oven at 171°C for an hourD) autoclavingE) freezing below 0°C


B)C)D)E)

42) Disinfectants that damage membranes include 42)A) phenolics.B) hydrogen peroxide.C) alcohol.D) iodine.E) both alcohol and phenolics.


B)C)D)E)

12

full file at http://testbankcorner.eu43) Hydrogen peroxide is a(n) 43)

A) sterilizing agent.B) disinfecting and sterilizing agent.C) disinfecting agent.D) ineffective method of disinfecting.E) antiseptic.


B)C)D)E)

44) Seventy percent alcohol is effective against 44)A) prions.B) protozoan cysts.C) enveloped viruses.D) bacterial endospores.E) nonenveloped viruses.


B)C)D)E)

45) Which of the following is NOT a desirable characteristic of an ideal antimicrobial agent? 45)A) It only arrests growth of vegetative cells.B) It is stable during storage.C) It acts quickly.D) It is harmless to humans.E) It is inexpensive.


B)C)D)E)

SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.

46) Microbial growth in jellies is inhibited by the (acidic/hypotonic/hypertonic) condition ofthe food.

46)

Answer: hypertonicExplanation:

47) Heavy metal and oxidizing agent disinfectants damage (proteins/DNA/membranes),interfering with microbial metabolism.

47)

Answer: proteinsExplanation:

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full file at http://testbankcorner.eu48) The process of freeze-drying microbes to preserve them is (lyophilization/dessication). 48)

Answer: lyophilizationExplanation:

49) Ultraviolet light penetrates (more/less) effectively than gamma rays. 49)Answer: lessExplanation:

50) Disinfectants known as (alcohols/oxidizers/aldehydes) have the chemical group -CHO,which reacts with and damages both proteins and nucleic acids.

50)

Answer: aldehydesExplanation:

51)

The antimicrobial chemical pictured above is a(n) (phenolic/surfactant/enzyme)compound found in many consumer products.

51)

Answer: phenolicExplanation:

52) Natural antiseptics such as pine or clove oil are examples of antimicrobial compoundscalled (alcohols/phenolics/detergents).

52)

Answer: phenolicsExplanation:

53) Elements such as iodine, chlorine, and bromine are examples of(oxidizers/halogens/metals), which are the basis for many effective antimicrobial agents.

53)

Answer: halogensExplanation:

54) A(n) (iodophor/halogen) is an iodine-containing organic compound found in suchantiseptics as Betadine.

54)

Answer: iodophorExplanation:

55) The effectiveness of sterilization procedures is evaluated using (prions/cysts/endospores)because of their resilience.

55)

Answer: endosporesExplanation:

56) The deadliest, most contagious microbes are studied under conditions of(BSL-4/BSL-3/BSL-2/BSL-1) containment.

56)

Answer: BSL-4Explanation:

14

full file at http://testbankcorner.eu57) The lowest temperature that kills all cells in a broth in 10 minutes is known as the

(microbial/thermal) death point.57)

Answer: thermalExplanation:

58) The amount of time needed to sterilize materials using moist heat is (more/less) than thetime needed to sterilize using dry heat.

58)

Answer: lessExplanation:

59) The process of heating milk or fruit juice to levels that kill any pathogenic microbes presentis known as (pasteurization/sanitization/lyophilization).

59)

Answer: pasteurizationExplanation:

60) The (endospores/cysts/prions) are the infectious agents most resistant to antimicrobialagents or processes.

60)

Answer: prionsExplanation:

TRUE/FALSE. Write 'T' if the statement is true and 'F' if the statement is false.

61) Removal of microbes from the skin is antisepsis. 61)Answer: True FalseExplanation:

62) Some viruses are inactivated by the same chemical or physical agents that damage cytoplasmicmembranes.

62)

Answer: True FalseExplanation:

63) The phenol coefficient is one of the most widely used measurements of an antimicrobial agent'seffectiveness.

63)


64) Refrigeration is an effective germicidal method. 64)Answer: True FalseExplanation:

65) The pH conditions under which a chemical disinfectant is used do not alter its efficacy. 65)Answer: True FalseExplanation:

66) No chemical or antimicrobial agents inactivate prions. 66)Answer: True FalseExplanation:

15

full file at http://testbankcorner.eu67) By themselves, soaps have only degerming activity, not antimicrobial activity. 67)


68) Antimicrobial agents usually work best at high temperatures and high pH levels. 68)Answer: True FalseExplanation:

69) Slow freezing is more damaging to microbial cells than quick freezing. 69)Answer: True FalseExplanation:

70) The decimal reduction time is the time required to kill all the microbes in a given sample. 70)Answer: True FalseExplanation:

ESSAY. Write your answer in the space provided or on a separate sheet of paper.

71) A student is shopping for antibacterial hand cleansers and is trying to decide which one to buy. One is a"waterless" hand gel containing 70% isopropanol, the second is an "antibacterial" hand soap containing triclosan(a phenolic), and the third is a wipe that lists benzethonium chloride (a synthetic quaternary ammonium salt) asthe active ingredient. Compare and contrast these cleansers in terms of the action of the antimicrobial ingredientand the level of disinfection (degerming, germistatic, germicidal).Answer: All three are germicidal, although not all to the same degree. The alcohol of the waterless hand cleaner is

a germicide that disrupts cytoplasmic membranes and denatures proteins. It is not effective againstbacterial endospores or fungal spores, and it has limited effect on nonenveloped viruses. The alcoholevaporates quickly, so the germicidal effect is short term. The waterless hand cleaner is anintermediate-level disinfectant and is not an effective degermer. The hand soap contains a phenolic,which also damages cytoplasmic membranes and denatures proteins, and is effective on the same rangeof microbes as the alcohol. Phenolics are intermediate-level disinfectants that persist on surfaces for longperiods of time, providing extended disinfection. If used with running water and the hands arevigorously rubbed, the hand soap can be an effective degermer. Synthetic "quats" (quaternaryammonium compounds) disrupt cell membranes. They are effective against fungi, enveloped viruses,and most bacteria, but not against nonenveloped viruses, nor on endospores. Quats are low-leveldisinfectants that are germicidal for some microbes. The action of using and discarding the wipe providessome degerming effect.

72) What is the in-use test, and why is it more useful than other methods of evaluating disinfectants?Answer: The in-use test is a method of evaluating antimicrobial agents such as disinfectants or antiseptics. It

involves collecting specimens from objects that need to be disinfected, both before and after thedisinfecting agent is applied. Then the specimens are inoculated into growth media, and the presence orabsence of growth is an indicator of the effectiveness of the agent. The in-use test is regarded as aninformative and useful test because it makes use of microbes that are actually found in the area ofconcern, and it gives a "real-life" picture of how the antimicrobial agent will work in that situation.Conversely, other tests, such as the disk-diffusion test or the use-dilution test, are not as useful becausethey rely on standardized conditions in a laboratory environment, and using test microbes that may ormay not have any relation to the actual microbes that need to be targeted by the antimicrobial agent.Additionally, in some environments, many microbes form biofilms that can affect the activity of anantimicrobial agent, and these biofilms are not normally present in standardized testing procedures.Therefore, although the in-use test is not as convenient or quick as the other types of tests, it is regardedas more useful.

16

full file at http://testbankcorner.eu73) Compare and contrast the nine major types of antimicrobial chemicals in terms of their effective on microbes.

Answer: Alcohols disrupt lipid membranes and denature proteins, are effective bactericidal, fungicidal agents,and inactivate enveloped viruses. They are effective in the range of 70 - 90% concentration and the effectis temporary due to evaporation. Aldehydes are highly effective germicidals that permanently damageDNA and proteins and gluteraldehyde can sterilize with long exposure. Enzymes can be effective atdestroying microbes, but tend to be limited in their effect to specific classes of microbes. For example,lysozyme is effective against bacteria, primarily Gram-positive bacteria. Gases like ethylene oxide arehighly effective germicidals that are also highly toxic to humans and are therefore only used underhighly controlled conditions. Halogens (iodine, chlorine, fluorine and bromine) are moderate leveldisinfectants that disrupt the structure of proteins, particularly enzymes, and thereby arrest metabolicactivity. Heavy metals are low level bacteriostatic and fungistatic agents that disrupt the activity ofproteins, slowing metabolic activity. Oxidizing agents are high level antimicrobials that denatureproteins and arrest metabolic activity. Phenolics are effective antimicrobials that damage proteins anddisrupt lipid membranes, and are long lasting. Surfactants range in effectiveness from low levelmicrobistatic soaps to more effective synthetic detergents like the quaternary ammonium compounds,which are microbicidal, disrupting cytoplasmic membranes.

74) Design an experiment to compare the effectiveness of a physical and a chemical method of disinfection.Answer: Answers will vary. Appropriate controls and methods should be included. An example is comparison of

filtration and chlorine bleach.Prepare a culture of bacteria of known cell concentration. Divide into three samples. Sample # 1 is thepositive control. Sample # 2 is filtered using a specified pore size filter (0.45 micron maximum pore size)and the filtrate collected into a sterile container. Chlorine bleach is added to Sample #3 followingmanufacturer's directions for dilution. The three samples are incubate, then the turbidity of each ismeasured to determine if growth is evident in the two treated samples compared to the untreatedsample.

75) Some sterilization procedures do not kill all the microbes that may be present. Explain how these proceduresmay for practical purposes still be considered sterilization.Answer: Theoretically, sterilization is the complete removal or destruction of all microbes in a particular

environment. These include dormant forms of microbes, such as bacterial endospores. However, from apractical standpoint, one must take other factors into account when deciding what is or is not sterile. Forexample, the particular application of the sterilized material must be considered. Although there may behyperthermophilic microbes present in canned foods after sterilization, they cannot grow and divide atnormal shelf temperatures; thus, their presence does not cause problems. In practice, only those microbesthat would cause problems either by their presence or by their continued growth and reproduction aregenerally the targets of sterilization methods. When these microbes have been eliminated, the goal ofsterilization can be said to have been reached.

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full file at http://testbankcorner.euAnswer KeyTestname: C9

1) E2) A3) A4) A5) C6) B7) B8) A9) A

10) D11) A12) B13) B14) E15) D16) C17) B18) E19) E20) E21) D22) D23) B24) E25) C26) D27) A28) B29) D30) D31) B32) D33) B34) C35) C36) D37) B38) C39) A40) C41) E42) E43) B44) C45) A46) hypertonic47) proteins48) lyophilization49) less50) aldehydes

18


51) phenolic52) phenolics53) halogens54) iodophor55) endospores56) BSL-457) thermal58) less59) pasteurization60) prions61) TRUE62) TRUE63) FALSE64) FALSE65) FALSE66) FALSE67) TRUE68) FALSE69) TRUE70) FALSE71) All three are germicidal, although not all to the same degree. The alcohol of the waterless hand cleaner is a germicide

that disrupts cytoplasmic membranes and denatures proteins. It is not effective against bacterial endospores or fungalspores, and it has limited effect on nonenveloped viruses. The alcohol evaporates quickly, so the germicidal effect isshort term. The waterless hand cleaner is an intermediate-level disinfectant and is not an effective degermer. The handsoap contains a phenolic, which also damages cytoplasmic membranes and denatures proteins, and is effective on thesame range of microbes as the alcohol. Phenolics are intermediate-level disinfectants that persist on surfaces for longperiods of time, providing extended disinfection. If used with running water and the hands are vigorously rubbed, thehand soap can be an effective degermer. Synthetic "quats" (quaternary ammonium compounds) disrupt cellmembranes. They are effective against fungi, enveloped viruses, and most bacteria, but not against nonenvelopedviruses, nor on endospores. Quats are low-level disinfectants that are germicidal for some microbes. The action ofusing and discarding the wipe provides some degerming effect.

72) The in-use test is a method of evaluating antimicrobial agents such as disinfectants or antiseptics. It involves collectingspecimens from objects that need to be disinfected, both before and after the disinfecting agent is applied. Then thespecimens are inoculated into growth media, and the presence or absence of growth is an indicator of the effectivenessof the agent. The in-use test is regarded as an informative and useful test because it makes use of microbes that areactually found in the area of concern, and it gives a "real-life" picture of how the antimicrobial agent will work in thatsituation. Conversely, other tests, such as the disk-diffusion test or the use-dilution test, are not as useful because theyrely on standardized conditions in a laboratory environment, and using test microbes that may or may not have anyrelation to the actual microbes that need to be targeted by the antimicrobial agent. Additionally, in some environments,many microbes form biofilms that can affect the activity of an antimicrobial agent, and these biofilms are not normallypresent in standardized testing procedures. Therefore, although the in-use test is not as convenient or quick as theother types of tests, it is regarded as more useful.

19


73) Alcohols disrupt lipid membranes and denature proteins, are effective bactericidal, fungicidal agents, and inactivateenveloped viruses. They are effective in the range of 70 - 90% concentration and the effect is temporary due toevaporation. Aldehydes are highly effective germicidals that permanently damage DNA and proteins andgluteraldehyde can sterilize with long exposure. Enzymes can be effective at destroying microbes, but tend to belimited in their effect to specific classes of microbes. For example, lysozyme is effective against bacteria, primarilyGram-positive bacteria. Gases like ethylene oxide are highly effective germicidals that are also highly toxic to humansand are therefore only used under highly controlled conditions. Halogens (iodine, chlorine, fluorine and bromine) aremoderate level disinfectants that disrupt the structure of proteins, particularly enzymes, and thereby arrest metabolicactivity. Heavy metals are low level bacteriostatic and fungistatic agents that disrupt the activity of proteins, slowingmetabolic activity. Oxidizing agents are high level antimicrobials that denature proteins and arrest metabolic activity.Phenolics are effective antimicrobials that damage proteins and disrupt lipid membranes, and are long lasting.Surfactants range in effectiveness from low level microbistatic soaps to more effective synthetic detergents like thequaternary ammonium compounds, which are microbicidal, disrupting cytoplasmic membranes.

74) Answers will vary. Appropriate controls and methods should be included. An example is comparison of filtration andchlorine bleach.Prepare a culture of bacteria of known cell concentration. Divide into three samples. Sample # 1 is the positive control.Sample # 2 is filtered using a specified pore size filter (0.45 micron maximum pore size) and the filtrate collected into asterile container. Chlorine bleach is added to Sample #3 following manufacturer's directions for dilution. The threesamples are incubate, then the turbidity of each is measured to determine if growth is evident in the two treatedsamples compared to the untreated sample.

75) Theoretically, sterilization is the complete removal or destruction of all microbes in a particular environment. Theseinclude dormant forms of microbes, such as bacterial endospores. However, from a practical standpoint, one must takeother factors into account when deciding what is or is not sterile. For example, the particular application of thesterilized material must be considered. Although there may be hyperthermophilic microbes present in canned foodsafter sterilization, they cannot grow and divide at normal shelf temperatures; thus, their presence does not causeproblems. In practice, only those microbes that would cause problems either by their presence or by their continuedgrowth and reproduction are generally the targets of sterilization methods. When these microbes have beeneliminated, the goal of sterilization can be said to have been reached.

20

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