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Pharmacology 1 > Antiseptics and Disinfectants > Flashcards

Antiseptics and Disinfectants Flashcards

1
Q

Contrast the terms sterilization, sanitization, disinfection, and antiseptic

A
  • sterilization: destruction of all forms of life (inclu. microorganisms)
  • sanitization: reduces pathogen load by 99.9%
  • disinfectant: destroys pathogenic organisms, usually on inanimate objects (reduces pathogen load by 99.99%)
  • antiseptic: prevents or arrests the development of microorganisms on living tissue
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2
Q

Be able to rank the relative resistance to disinfection of various etiologic agents.

A
  • low level: medium sized lipid viruses (enveloped), vegetative bacteria, fungi, small non-lipid viruses (unenveloped)
  • intermediate level: tubercle bacilli, coccidial oocysts, protozoal cysts
  • high level: bacterial spores
  • extremely resistant: prions (survives most sterilization methods, including rendering)
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3
Q

How effective, relatively speaking, are dry heat, boiling water, and autoclaving as sterilization
methods?

A
  • dry heat: inferior to moist heat, causes drying of cells, limited number of items can withstand the temperatures (320-340 F)
  • boiling: kills vegetative cells of bacteria, fungi, protozoan trophozoites, and most viruses (temp cannot exceed 100 C at sea level)
  • autoclaving: standard method, moist heat under pressure, addition of ethylene oxide exhibits bactericidal and sporicidal activity
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4
Q

What are the risks associated with the use of ethylene oxide as a sterilization agent?

A

Toxicity, carcinogenicity, and explosive risk require special equipment and venting for proper use

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5
Q

Why is “peroxide plasma sterilization” replacing ethylene oxide as the preferred method of
sterilizing heat sensitive items?

A

Hydrogen peroxide at 58% in the presence of an electromagnetic field becomes a gas plasma
- has a larger safety margin than ethylene oxide

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6
Q

What size micron filter should be used to filter fluids in order to remove bacteria and fungi?What
etiologic agents will filtration not remove?

A
  1. 22 and 0.45um pores to filter most bacteria
    - do not retain spirochetes, mycoplasmas, viruses
    - mostly used to sterilize liquids that will not withstand autoclaving
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7
Q

UV light is sometimes used in biocontainment hoods for sterilization/disinfection.What are its limitations?

A

Works to break molecular bonds within microorganismal DNA

  • only effective for line of sight surface disinfection
  • directly looking at UV light can damage retina and cornea
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8
Q

Does gamma ray sterilization leave a treated object radioactive?

A

No, dislodges electrons from atoms and forms ions leading to free radical production

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9
Q

Name the only high‐level disinfectant in common use in veterinary practice.

A

Glutaraldehyde 2% (Cidex)

  • penetrates spores better than formaldehyde, item must be rinsed with sterile saline or water prior to use on a patient
  • requires 10-30 minutes of contact time, exposure of 6-10 hours produces sterilization
  • most commonly used for endoscopes
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10
Q

Contrast which bacteria are killed for a high‐level versus a low‐level disinfectant.

A
  • high level: kills bacterial spores. used on critical items that impart risk of infection to patient if contaminated
  • low level: effective on vegetative microorganisms but not spores or tubercle bacilli. also used on noncritical items that carry limited risk of inducing infection
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11
Q

How does an iodine “tincture” differ from an iodine “solution”?

A

Tinctures contain ethanol and are more efficacious, but more toxic to tissues than aqueous solutions

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12
Q

Povidone iodine solutions can be used for use as wound lavage solutions over a wide range of v/vdilutions. Name the upper and lower limits of that range.

A

Less toxic to tissues, and is the only iodine recommended for use in wounds

  • 0.1 to 1% used to lavage wounds
  • 10% solution diluted 1:10 to 1:100 v/v in water
  • least residual activity of the antiseptics
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13
Q

Name an antiseptic restricted to use on skin (not wounds) that accumulates with time having a long
residual activity.

A
  • chlorhexadine: scrub formulation used only on skin (1:40 v/v dilution)
  • benzoyl peroxide: only against gram-pos bacteria (pyodermas, follicular flushing), most repository of the skin antiseptics!
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14
Q

How does EDTA enhance the activity of an antibiotic used topically?

A

Is a chelator of di and trivalent cations, which are required by bacteria (pseudomonas, proteus, e coli, and staph) to maintain cell wall integrity

  • combo with Tris to adjust pH
  • synergistic with antibiotics by damaging the cell membrane (MICs decrease by 100x)
  • used in multi-resistant bladder infections, wounds, fistulas
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15
Q

Pseudomonas and yeast are unusually sensitive to what common household food item that can be
used as an antiseptic?

A

Acetic acid - 3% solution recommended, or distilled white vinegar of 5%

  • well tolerated below 5%
  • gram negs are also affected
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16
Q

What agents are often used a foot baths in cattle and sheep?(You do not have to know the
concentrations used.)How does dirt and manure affect the efficacy of these foot baths?

A
  • zinc sulfate: used in sheep to avoid copper exposure
  • copper sulfate: most common, some concern about environmental contamination
  • formalin: good for heel warts, toughens sole (overuse can crack hoof wall)
  • dirt and manure will decrease efficacy*
17
Q

What v/v dilution of chlorhexadine is used as an antiseptic, particularly to lavage wounds?

A

1:40 v/v dilution is considered to be non-toxic to tissues

18
Q

What are the ingredients found in a Modified Dakin’s antiseptic solutions?

A

Dilute solution of sodium hypochlorite

  • used as antiseptic for wounds (surface only!) and for debridement
  • buffer with sodium bicarbonate (1/2 teaspoon per 32 ounces)
19
Q

Name two agents historically used as wound antiseptics that are now known to be too toxic to the tissues for this use.

A
  • benzoyl peroxide: only safe for pyodermas
  • hydrogen peroxide: only clean intact skin
  • free iodine solutions
20
Q

What category of disinfectant should be used cautiously especially around cats?

A

Phenols

- lysol, beaucoup, amphyl

21
Q

Name two disinfectants that maintain their activity in organic debris.

A
  • phenols

- chlorhexadine: must be in contact for at least 5 minutes

22
Q

In what disease conditions is silver sulfadiazine commonly used?

A

Burns, wounds, otically

23
Q

Discuss alcohol as a disinfectant, including its categorization (low, intermediate, high), relative onset, and types of alcohol (isopropyl, ethyl, and methyl alcohol) and concentration percentages for best efficacy.

A

Ethanol or isopropyl

  • low to intermediate: effective against most vegetative bacteria and enveloped viruses –> rapid killing of susceptible organisms
  • 70% concentration is optimal, presence of water enhances killing action –> good skin antiseptic with cleaning benefit (hair must be removed and alcohol must evaporate)
  • function: denature proteins
24
Q

Chlorhexadine

A

Good against gram-pos, variable activity against fungi and viruses, NO activity against spores!

  • low level disinfectant
  • gluconate (scrub) or diacetate (solution)
  • function: disrupts cell membrane
  • maintains activity in organic matter! looses activity in anionic detergents
25
Q

Benzoyl peroxide

A

Active against gram pos bacteria

  • too toxic for tissues!
  • used on pyodermas (follicular flushing)
  • the most repository skin antiseptic (only OTC that has an antibacterial effect)
  • drying or irritation if overused
  • shampoo or lotions up to 10% (2.5% commonly used)
26
Q

Hydrogen peroxide

A

Used to clean intact skin, too toxic to tissues for use as an antiseptic!!
- 3% solution

27
Q

EDTA

A

Chelates cations, damages bacterial cell wall creating a synergistic effect with antibiotics
- used in otitis externa, multi-resistant bladder infections as infusion, wounds, and fistulas

28
Q

Povidone iodine

A

Complexed iodine compounds (iodophores)

  • bound to high MW carrier
  • increased solubility, improved wetting properties –> less toxic to tissues and the only iodine recommended for use in wounds!!
  • scrub used as skin prep
  • 0.1-1% used to lavage wounds
  • least residual activity of the antiseptics
  • bacterial resistance to iodophores has been found, alternate antiseptics when doing daily lavages
29
Q

What are the 9 common disinfectant mistakes?

A
  • eyeballing disinfectant solution mixtures
  • failing to reach designated contact time
  • confusing sanitized with disinfected
  • not knowing the shelf life of the disinfectant being used
  • topping off diluted disinfectant bottles, rather than starting each time with a cleaned bottle and fresh batch
  • mixing cleaning chemicals
  • spraying a surface and then wiping it with a dry cloth
  • not giving or receiving product-specific training to vet team members
  • not getting buy-in from team members on a switch to a new product

Pharmacology 1 (15 decks)

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