CH 13 Review Questions

22. A medical item that comes into contact with intact skin and does not penetrate sterile tissues or come into contact with mucous membranes is called a(n) ________ item.

22. noncritical

23. The goal of ________ ________ protocols is to rid canned produce of Clostridium botulinum endospores.

23. commercial sterilization

24. In an autoclave, the application of pressure to ________ is increased to allow the steam to achieve temperatures above the boiling point of water.

24. steam

25. Doorknobs and other surfaces in clinical settings are often coated with ________, ________, or ________ to prevent the transmission of microbes.

25. copper, nickel, zinc

26. If a chemical disinfectant is more effective than phenol, then its phenol coefficient would be ________ than 1.0.

26. greater

27. If used for extended periods of time, ________ germicides may lead to sterility.

27. high-level

28. In the disk-diffusion assay, a large zone of inhibition around a disk to which a chemical disinfectant has been applied indicates ________ of the test microbe to the chemical disinfectant.

28. susceptibility or sensitivity

35. Which solution of ethyl alcohol is more effective at inhibiting microbial growth: a 70% solution or a 100% solution? Why?

70%; gains trust then takes em out at the knees(Alcohols coagulate proteins-Too much can over too it and defeat purpose)

Which of the following microbial control methods does not actually kill microbes or inhibit their growth but instead removes them physically from samples? A. filtration B. desiccation C. lyophilization D. nonionizing radiation

A. filtration

10. Which of the following peroxygens is widely used as a household disinfectant, is inexpensive, and breaks down into water and oxygen gas? A. hydrogen peroxide B. peracetic acid C. benzoyl peroxide D. ozone

A. hydrogen peroxide

Which of the following types of medical items requires sterilization? A. needles B. bed linens C. respiratory masks D. blood pressure cuffs

A. needles

The effectiveness of chemical disinfectants has historically been compared to that of which of the following? A. phenol B. ethyl alcohol C. bleach D. formaldehyde

A. phenol

34. Which is more effective at killing microbes: autoclaving or freezing? Explain.

Autoclaving; it's the most effective method of sterilization allowing moist heat on large scale without damaging itemsFreezing just stops growth of microbes

Which biosafety level is appropriate for research with microbes or infectious agents that pose moderate risk to laboratory workers and the community, and are typically indigenous? A. BSL-1 B. BSL-2 C. BSL-3 D. BSL-4

B. BSL-2

Which of the following is suitable for use on tissues for microbial control to prevent infection? A. disinfectant B. antiseptic C. sterilant D. water

B. antiseptic

12. Bleach is an example of which group of chemicals used for disinfection? A. heavy metals B. halogens C. quats D. bisbiguanides

B. halogens

Which of the following chemical food preservatives is used in the wine industry but may cause asthmatic reactions in some individuals? A. nitrites B. sulfites C. propionic acid D. benzoic acid

B. sulfites

Which of the following refers to a disinfecting chemical dissolved in alcohol? A. iodophor B. tincture C. phenolic D. peroxygen

B. tincture

40. When plotting microbial death curves, how might they look different for bactericidal versus bacteriostatic treatments?

Bactericidal: kills completely Bacteriostatic: stops growth without killing

41. What are the benefits of cleaning something to a level of cleanliness beyond what is required? What are some possible disadvantages of doing so?

Benefits: maintaining health Disadvantages: killing all microbes is bad, they can build resistance, stripping all microbes can result in death

Which chemical disinfectant works by methylating enzymes and nucleic acids and is known for being toxic and carcinogenic? A. sorbic acid B. triclosan C. formaldehyde D. hexaclorophene

C. formaldehyde

Which type of test is used to determine whether disinfectant solutions actively used in a clinical setting are being used correctly? A. disk-diffusion assay B. phenol coefficient test C. in-use test D. use-dilution test

C. in-use test

Which of the following refers to a germicide that can kill vegetative cells and certain enveloped viruses but not endospores? A. high-level germicide B. intermediate-level germicide C. low-level germicide D. sterilant

C. low-level germicide

The decimal reduction time refers to the amount of time it takes to which of the following? A. reduce a microbial population by 10% B. reduce a microbial population by 0.1% C. reduce a microbial population by 90% D. completely eliminate a microbial population

C. reduce a microbial population by 90%

Which of the following terms is used to describe the time required to kill all of the microbes within a sample at a given temperature? A. D-value B. thermal death point C. thermal death time D. decimal reduction time

C. thermal death time

29. What are some characteristics of microbes and infectious agents that would require handling in a BSL-3 laboratory?

Contaminated air requiring constant supple of clean air, pathogenic/possibly need vaccination for microbe they are working with, air/blood born, special gear/training, use under hood

Which of the following best describes a microbial control protocol that inhibits the growth of molds and yeast? A. bacteriostatic B. fungicidal C. bactericidal D. fungistatic

D. fungistatic

Which of the following methods brings about cell lysis due to cavitation induced by rapid localized pressure changes? A. microwaving B. gamma irradiation C. ultraviolet radiation D. sonication

D. sonication

19. T/F Moist-heat sterilization protocols require the use of higher temperatures for longer periods of time than do dry-heat sterilization protocols do.

FALSE

20. T/F Soaps are classified as disinfectants.

FALSE

T/F Sanitization leaves an object free of microbes.

FALSE

32. What is the advantage of HTST pasteurization compared with sterilization? What is an advantage of UHT treatment?

HTST advantage: lowers bacterial numbers while preserving the quality of the milkUHT advantage: can be stored for long time in sealed containers without refrigerated (regions in which access to refrigeration is limited)

38. Why were chemical disinfectants once commonly compared with phenol?

Historically they Often compared disinfections with phenol because phenol was the first chemical agent used

37. What is the advantage of using an iodophor rather than iodine or an iodine tincture?

Iodophor: compound of Iodine complexed with an organic molecule, increasing iodines stability and in turn its efficacy

45. Why is the use of skin disinfecting compounds required for surgical scrubbing and not for everyday handwashing?

It is more persistent than iodophors, providing long lasting antimicrobial activity and acts faster-Over using daily would damage and build resistance

30. What is the purpose of degerming? Does it completely eliminate microbes?

Microbial numbers are significantly reduced by gently scrubbing living tissue with mild chemical to aboid transmission of pathogenic microbes(ex washing hands, alcohol swab on injection site) it removes MOST( but not all) microbes from surface

31. What are some factors that alter the effectiveness of a disinfectant?

length of exposure, concentration, temperature, pH

39. Why is length of exposure to a chemical disinfectant important for its activity?

longer exposure means increasing efficacy of chemical disinfectant

18. T/F Ionizing radiation can penetrate surfaces, but nonionizing radiation cannot.

TRUE

21. T/F Mercury-based compounds have fallen out of favor for use as preservatives and antiseptics.

TRUE

36. When might a gas treatment be used to control microbial growth instead of autoclaving? What are some examples?

Used in the sterilization of sensitive items; HighEfficiencyParticulateAirFilters(HEPA), Radiation, Slow freezing, osmotic pressure

33. How does the addition of salt or sugar help preserve food?

Very high concentrations of sugar or salt cause the available amount of water in microbial cells to reduce dramatically because water is drawn from low solute concentration (inside cell) to areas of high solute concentration (outside cell)

42. In 2001, endospores of Bacillus anthracis, the causative agent of anthrax, were sent to government officials and news agencies via the mail. In response, the US Postal Service began to irradiate mail with UV light. Was this an effective strategy? Why or why not?

Yes; UV light can be used to sterilize; cells must be exposed directly to the light source because UV light doesn't penetrate surfaces unless direct contact