Test bank for 2013 microbiology with diseases by taxonomy, 4th edition

39 A use-dilution test B phenol coefficient C in-use test D microbial death rate E thermal death point Answer: A Explanation: A B C D E 40 Which of the following is the most appropriate

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Exam

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: E

Explanation: A)

B) C) D) E) 2) Which of the following infectious agents is least resistant to destruction by chemical methods? 2)

A) enveloped viruses

B) fungal spores

C) nonenveloped viruses

D) vegetative bacterial cells

E) bacterial endospores

Answer: A

Explanation: A)

B) C) D) E) 3) Which of the following is used for microbial control in fresh fruits and vegetables? 3)

A) gamma rays

B) ultraviolet light

C) microwaves

D) electron beams

E) X-rays

Answer: A

Explanation: A)

B) C) D) E)

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4) 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 nitrate

B) hydrogen peroxide

C) beta-propiolactone

D) hexachlorophene

E) thimerosal

Answer: A

Explanation: A)

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: C

Explanation: A)

B) C) D) E) 6) An instrument that will come into contact with only the skin of a patient should be disinfected with

A) degerming agent only

B) low-level germicide

C) germistatic agent only

D) intermediate-level germicide

E) high-level germicide

Answer: B

Explanation: A)

B) C) D) E)

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7) 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.

Answer: B

Explanation: A)

B) C) D) E) 8) Which of the following is a target of pasteurization? 8)

A) Brucella melitensis

B) Neisseria gonorrhoeae

C) Chlamydia trachomatis

D) Bacillus stearothermophilus

E) Clostridium botulinum

Answer: A

Explanation: A)

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

Answer: A

Explanation: A)

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: D

Explanation: A)

B) C) D) E)

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11) Which of the following is a sterilizing agent? 11)

A) peracetic acid

B) ozone and hydrogen peroxide

C) hydrogen peroxide

D) ozone

E) dish soap

Answer: A

Explanation: A)

B) C) D) E) 12) Which of the following types of radiation is nonionizing and has the shortest wavelength? 12)

A) gamma rays

C) infrared radiation

D) X-rays

E) microwaves

Answer: B

Explanation: A)

B) C) D) E) 13) Which of the following describes flash pasteurization? 13)

A) heating at 72°C for 15 minutes

B) heating at 72°C for 15 seconds

C) heating at 134°C for one second

D) passing liquid through steam at 140°C

E) heating at 63°C for 30 minutes

Answer: B

Explanation: A)

B) C) D) E) 14) Glutaraldehyde is used for 14)

A) sterilization

B) sanitization

C) disinfection

D) antisepsis

E) both disinfection and sterilization

Answer: E

Explanation: A)

B) C) D) E)

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15) 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

Answer: D

Explanation: A)

B) C) D) E) 16) The endospores of which of the following microbes are used to measure the effectiveness of

autoclave sterilization? 16)

A) Mycobacterium bovis

B) Clostridium botulinum

C) Bacillus stearothermophilus

D) Pseudomonas aeruginosa

E) Neisseria gonorrhoeae

Answer: C

Explanation: A)

B) C) D) E) 17) Which of the following would be used to sterilize a mattress? 17)

A) heavy metals

B) ethylene oxide

C) formaldehyde

D) radiation

E) autoclaving

Answer: B

Explanation: A)

B) C) D) E) 18) Which of the following is NOT a feature associated with filtration? 18)

A) use of HEPA filters to filter air

B) ability of some filters to trap viruses and proteins

C) nitrocellulose or plastic membrane filters

D) sterilization of heat-sensitive materials

E) varying thicknesses of membrane filters used

Answer: E

Explanation: A)

B) C) D) E)

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19) Disinfecting agents naturally produced by microorganisms are 19)

A) aldehydes

B) triclosans

C) quats

D) halogens

E) antimicrobials

Answer: E

Explanation: A)

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

Answer: E

Explanation: A)

B) C) D) E) 21) Which of the following can be used to disinfect air? 21)

A) HEPA filters

C) ethylene oxide

D) both HEPA filters and ultraviolet light

E) both ethylene oxide and ultraviolet light

Answer: D

Explanation: A)

B) C) D) E)

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22) 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 considered

sterile?

22)

A) 10 minutes

B) 9 minutes

C) 12 minutes

D) 16.5 minutes

E) 20 minutes

Answer: D

Explanation: A)

B) C) D) E) 23) Which of the following is the most difficult to inactivate? 23)

A) fungus spores

B) bacterial endospores

C) protozoal cysts

D) nonenveloped viruses

E) enveloped viruses

Answer: B

Explanation: A)

B) C) D) E) 24) is the physical removal of microbes 24)

A) Antisepsis

B) Sanitization

C) Disinfection

D) Sterilization

E) Degerming

Answer: E

Explanation: A)

B) C) D) E)

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25) 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

Answer: C

Explanation: A)

B) C) D) E) 26) may be achieved using chlorine dioxide 26)

A) Sterilization

B) Degerming

C) Antisepsis

D) Disinfection

E) Both antisepsis and degerming

Answer: D

Explanation: A)

B) C) D) E) 27) A scientist develops a new medication that is a protein compound and that must be administered

by injection Which of the following would be the most effective and safest means of preparing a

sterile solution of the new medication?

27)

A) filtration

B) autoclaving

C) dilution with alcohol

D) ultraviolet irradiation

E) lyophilization

Answer: A

Explanation: A)

B) C) D) E)

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28) Which of the following is used to sterilize items that should not, or cannot, be exposed to heat or

A) hydrogen peroxide

B) ethylene oxide

C) calcium hypochlorite

D) triclosan

E) formaldehyde

Answer: B

Explanation: A)

B) C) D) E) 29) Silvadene, a topical treatment for burns, contains 1% silver What category of chemical control

agent is in Silvadene? 29)

A) halogens

B) aldehydes

C) oxidizing agents

D) heavy metals

E) surfactants

Answer: D

Explanation: A)

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

Answer: D

Explanation: A)

B) C) D) E)

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31) The use of lysozyme during the preparation of cheeses and wines is effective in reducing the

A) all microbes

B) bacteria

C) fungi

D) viruses

E) prions

Answer: B

Explanation: A)

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

Answer: D

Explanation: A)

B) C) D) E) 33) Which of the following antimicrobial agents is the most toxic to humans? 33)

A) 70% alcohol

B) ethylene oxide

C) iodophors

D) chloramines

E) quats

Answer: B

Explanation: A)

B) C) D) E) 34) The compound ethylene oxide is used in 34)

A) sanitization

B) disinfection

C) sterilization

D) degerming

E) antisepsis

Answer: C

Explanation: A)

B) C) D) E)

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35) Aseptic means 35)

A) free of all microbes

B) clean

C) free of pathogens

D) sanitized

E) sterile

Answer: C

Explanation: A)

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

Answer: D

Explanation: A)

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

Answer: B

Explanation: A)

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

Answer: C

Explanation: A)

B) C) D) E)

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39) 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 test

B) phenol coefficient

C) in-use test

D) microbial death rate

E) thermal death point

Answer: A

Explanation: A)

B) C) D) E) 40) Which of the following is the most appropriate pairing of microbe and biosafety level? 40)

A) tuberculosis, BSL-1

B) E coli, BSL-3

C) methicillin-resistant Staphylococcus aureus (MRSA), BSL-2

D) anthrax, BSL-1

E) Ebola, BSL-2

Answer: C

Explanation: A)

B) C) D) E) 41) Which of the following is bacteriostatic? 41)

A) flash Pasteurization

B) filtration

C) heating in an oven at 171°C for an hour

D) autoclaving

E) freezing below 0°C

Answer: E

Explanation: A)

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

Answer: E

Explanation: A)

B) C) D) E)

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43) Hydrogen peroxide is a(n) 43)

A) sterilizing agent

B) disinfecting and sterilizing agent

C) disinfecting agent

D) ineffective method of disinfecting

E) antiseptic

Answer: B

Explanation: A)

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

Answer: C

Explanation: A)

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

Answer: A

Explanation: A)

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 of

Answer: hypertonic

Explanation:

47) Heavy metal and oxidizing agent disinfectants damage (proteins/DNA/membranes),

interfering with microbial metabolism 47)

Answer: proteins

Explanation:

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48) The process of freeze-drying microbes to preserve them is (lyophilization/dessication) 48)

Answer: lyophilization

Explanation:

49) Ultraviolet light penetrates (more/less) effectively than gamma rays 49)

Answer: less

Explanation:

50) Disinfectants known as (alcohols/oxidizers/aldehydes) have the chemical group -CHO,

which reacts with and damages both proteins and nucleic acids 50)

Answer: aldehydes

Explanation:

51)

The antimicrobial chemical pictured above is a(n) (phenolic/surfactant/enzyme)

compound found in many consumer products

51)

Answer: phenolic

Explanation:

52) Natural antiseptics such as pine or clove oil are examples of antimicrobial compounds

called (alcohols/phenolics/detergents) 52)

Answer: phenolics

Explanation:

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: halogens

Explanation:

54) A(n) (iodophor/halogen) is an iodine-containing organic compound found in such

antiseptics as Betadine 54)

Answer: iodophor

Explanation:

55) The effectiveness of sterilization procedures is evaluated using (prions/cysts/endospores)

because of their resilience 55)

Answer: endospores

Explanation:

56) The deadliest, most contagious microbes are studied under conditions of

(BSL-4/BSL-3/BSL-2/BSL-1) containment 56)

Answer: BSL-4

Explanation:

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57) The lowest temperature that kills all cells in a broth in 10 minutes is known as the

(microbial/thermal) death point 57)

Answer: thermal

Explanation:

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

time needed to sterilize using dry heat 58)

Answer: less

Explanation:

59) The process of heating milk or fruit juice to levels that kill any pathogenic microbes present

is known as (pasteurization/sanitization/lyophilization) 59)

Answer: pasteurization

Explanation:

60) The (endospores/cysts/prions) are the infectious agents most resistant to antimicrobial

agents or processes 60)

Answer: prions

Explanation:

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 False

Explanation:

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

Answer: True False

Explanation:

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

Answer: True False

Explanation:

64) Refrigeration is an effective germicidal method 64)

Answer: True False

Explanation:

65) The pH conditions under which a chemical disinfectant is used do not alter its efficacy 65)

Answer: True False

Explanation:

66) No chemical or antimicrobial agents inactivate prions 66)

Answer: True False

Explanation:

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67) By themselves, soaps have only degerming activity, not antimicrobial activity 67)

Answer: True False

Explanation:

68) Antimicrobial agents usually work best at high temperatures and high pH levels 68)

Answer: True False

Explanation:

69) Slow freezing is more damaging to microbial cells than quick freezing 69)

Answer: True False

Explanation:

70) The decimal reduction time is the time required to kill all the microbes in a given sample 70)

Answer: True False

Explanation:

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) as the active ingredient Compare and contrast these cleansers in terms of the action of the antimicrobial ingredient and 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 against bacterial endospores or fungal spores, and it has limited effect on nonenveloped viruses The alcohol evaporates quickly, so the germicidal effect is short term The waterless hand cleaner is an

intermediate-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 range

of microbes as the alcohol Phenolics are intermediate-level disinfectants that persist on surfaces for long periods of time, providing extended disinfection If used with running water and the hands are

vigorously rubbed, the hand soap can be an effective degermer Synthetic "quats" (quaternary ammonium 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-level disinfectants that are germicidal for some microbes The action of using and discarding the wipe provides some 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 the disinfecting agent is applied Then the specimens are inoculated into growth media, and the presence or absence of growth is an indicator of the effectiveness of the agent The in-use test is regarded as an informative and useful test because it makes use of microbes that are actually found in the area of concern, 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 because they rely on standardized conditions in a laboratory environment, and using test microbes that may or may 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 an antimicrobial 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 regarded

as more useful

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