Controlling Microbial Growth
A nurse prepares an area of skin for injection by scrubbing it with an alcohol swab; this process is called
A. sterilization.
B. disinfection.
C. degerming.
D. sanitization.
Which of the following terms includes the destruction of bacterial endospores?
A. pasteurization
B. sanitization
C. sterilization
D. antisepsis
Antimicrobial agents that disrupt the cell membrane will also damage
A. cellular enzymes.
B. the viral envelope.
C. the cell wall.
D. cellular DNA.
Which of the following statements concerning microbial death is correct?
A. It is the same for all microbes under all conditions.
B. It can be plotted on a semilogarithmic graph.
C. It is a loss of reproductive ability that lasts for 12-24 hours.
D. All of the above are correct.
A membrane filter with a pore size of 1.2 micrometers would trap all of the following EXCEPT:
A. yeasts.
B. bacteria.
C. multicellular fungi.
D. protozoa.
All of the following would contribute to the increased efficiency of an antimicrobial agent EXCEPT:
A. higher pH.
B. higher concentrations of the agent.
C. longer exposure to cells.
D. higher temperatures.
Which of the following microbial control procedures creates pyrimidine dimers in DNA?
A. heavy metals
B. autoclaving
C. ionizing radiation
D. nonionizing radiation
An experimental disinfectant has a phenol coefficient of 10 against E. coli. Which of the following is the
most accurate interpretation of this data?
A. The disinfectant is better than phenol.
B. The disinfectant is worse than phenol.
C. The disinfectant is 10 times better than phenol.
D. Nothing can be concluded until an in-use test is done.
Which of the following tests gives the most accurate picture of the activity of a disinfectant in a
particular environment or application?
A. the phenol coefficient
B. the use-dilution test
C. the decimal reduction test
D. the in-use test
All of the following statements concerning autoclaving are true EXCEPT:
A. Under 15 p.s.i. of pressure, water boils at 121oC.
B. Large volumes or solid substances require longer autoclaving times.
C. In order for an item to be sterilized in an autoclave, steam must contact all its surfaces.
D. Any material that needs to be sterilized should be autoclaved.
All of the following microbes are killed by pasteurization EXCEPT:
A. E. coli.
B. Mycobacterium bovis.
C. Brucella melitensis.
D. Bacillus stearothermophilus.
A particular machine passes milk through steam at a temperature of 140OC for one second and then
cools it rapidly. This is an example of
A. ultrahigh-temperature pasteurization.
B. pasteurization.
C. ultrahigh-temperature sterilization.
D. autoclaving.
All of the following microbial control methods are bacteriostatic EXCEPT:
A. desiccation.
B. lyophilization.
C. refrigeration.
D. ionizing radiation.
All of the following are examples of ionizing radiation EXCEPT:
A. ultraviolet light.
B. gamma rays.
C. electron beams.
D. X rays.
Which of the following antimicrobial agents can disrupt the cell membrane?
A. quaternary ammonium compounds
B. aldehydes
C. halogens
D. heavy metals
Which of the following compounds is no longer used to preserve vaccines?
A. silver nitrate
B. thimerosal
C. calcium hypochlorite
D. hexachlorophene
All of the following antimicrobial agents function by chemically cross-linking and inactivating proteins
and nucleic acids EXCEPT:
A. glutaraldehyde.
B. beta-propiolactone.
C. ethylene oxide.
D. peracetic acid.
Which of the following is NOT a gaseous antimicrobial agent?
A. glutaraldehyde
B. ethylene oxide
C. beta-propiolactone
D. propylene oxide
Which of the following is an incorrect pairing?
A. bromine: hot tub disinfectant
B. chloramine: disinfection of municipal water supplies
C. iodophor: alcohol solution of iodine
D. chlorine dioxide: antimicrobial gas
The decimal reduction time for endospores of Clostridium botulinum is 0.204 minutes at 121OC. How
long should it take to reduce a population of 1015 endospores to 1 endospore?
A. 1.3 minutes
B. 2.5 minutes
C. 3.1 minutes
D. 2.0 minutes