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PR3151 CA1 > IC2 > Flashcards

IC2 Flashcards

1
Q

what is sterilisation

A

process that destroy/eliminate all form of microbial life

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2
Q

what is disinfection

A

process that eliminate many/all microorganism except bacterial spores or inanimate objects

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3
Q

cleaning

A
  • removal of visible soil
  • manual/mechanical w water & detergent/enzymatic product
  • required before disinfection/sterilisation
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4
Q

biocides

A
  • fight microorganisms on non living surfaces & human skin
  • broader spectrum of activity than antibiotics
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5
Q

factors affecting efficacy of disinfection & sterilisation - number of microbes

A
  • larger number = longer time
  • prioir cleaning = reduce no. of microorganisms = increase margin of safety & shorten exposure time to kill microbial load
  • location of microbes: direct contact, not effective if crevice/hinge
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6
Q

factors affecting efficacy of disinfection & sterilisation - innate resistance of microorganism

A
  • spores more resistant to disinfectant (spore coat & cortex act as barrier
  • mycobacteria waxy cell wall = prevent disinfectant entry
  • gram -ve bacteria outer membrane = act as barrier to uptake of disinfectant
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7
Q

factors affecting efficacy of disinfection & sterilisation - concentration & potency of disinfectant

A
  • more concentrated = greater efficacy = shorter time to achieve disinfection
  • process X linear: 1/2 disinfectant concentration doesn’t mean double time required
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8
Q

factors affecting efficacy of disinfection & sterilisation - physical & chemical factor

A

1) temp increase

  • increase activity but possible degradation

2) pH increase

  • alter disinfectant molecule/cell surface
  • improve activity for some (glutaraldehyde, quat ammonium compounds)
  • decrease activity for some (phenol, hypochlorite, iodine)

3) humidity

  • important for gaseous disinfectant (ethanol, chlorine dioxide, formaldehyde)

4) water hardness

  • divalent cations interact w disinfectant -> form insoluble precipitate -> reduce rate of kill
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9
Q

factors affecting efficacy of disinfection & sterilisation - organic & inorganic matter

A
  • chemical reaction between germicide
  • protection by occlusion into salt crystals
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10
Q

factors affecting efficacy of disinfection & sterilisation - duration of exposure

A

exposed for appropriate minimum contact time

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11
Q

factors affecting efficacy of disinfection & sterilisation - biofilms

A
  • microbial communities that are tightly attached to surfaces, X be easily removed
  • mechanisms of biofilm development:
    1) old layers
    2) genotype variation
    3) neutralising enzyme
    4) physiologic condition
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12
Q

factors affecting efficacy of disinfection & sterilisation - general list of all the factors

A

1) number of microbes
2) innate resistance
3) concentration & potency of disinfectant
4) physical & chemical factor
5) organic & inorganic matter
6) duration of exposure
7) biofilms

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13
Q

types of active ingredients in disinfectant - alcohol - general

A

rapid broad spectrum antimicrobial activity against vegetative bacteria (mycobacteria), viruses, fungi BUT not sporicidal

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14
Q

types of active ingredients in disinfectant - alcohol - uses

A

1) hard-surface disinfection
2) skin antisepsis (+/- other excipients/biocides cuz alcohol irritant)

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15
Q

types of active ingredients in disinfectant - alcohol - MOA

A

1) Denaturation of protein

  • increased by water (dehydrogenase of E coli, lag phase of enterobacter aerogenes

2) bacteriostatic by inhibition of metabolites essential for rapid cell division

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16
Q

types of active ingredients in disinfectant - alcohol - types

A

1) isopropyl alcohol
- greater lipophilic properties than ethyl alcohol & less active against hydrophilic viruses (polio)

2) ethanol

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17
Q

types of active ingredients in disinfectant - alcohol - disadvantages

A

1) not sporicidal
2) microbial activity affected by organic matter
3) volatile (may affect contact time)(

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18
Q

types of active ingredients in disinfectant - ammonia - function

A

general purpose cleaner for many surfaces (Glass, stainless steel)

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19
Q

types of active ingredients in disinfectant - ammonia - MOA

A

-saponifying liquids within envelopes of microorganisms
- equilibrium: in 1 mole of ammonia, 0.42% ammonia converted to ammonium

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20
Q

types of active ingredients in disinfectant - ammonia - disadvantages

A
  • household ammonia irritant for eyes & gastric system
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21
Q

types of active ingredients in disinfectant - aldehyde - MOA

A

alkylation of sulfhydryl, hydroxyl, carboxyl, amino groups of microorganisms -> alter RNA, DNA, protein synthesis

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22
Q

types of active ingredients in disinfectant - aldehyde - actions against different microorganism

A

1) bacterial spore

  • low concentration: inhibit germination
  • high concentration: sporicidal (interact w outer cell layer)

2) mycobacteria

  • probably involve mycobacterial cell wall

3) other nonsporulating bacteria

  • strong association with outer layers of gram pos & neg bacteria, cross linking of protein amino groups, inhibition of transport processes into cell

4) fungi

  • fungal cell wall: interaction w chitin

5) viruses

  • protein DNA cross link
  • capsid changes
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23
Q

types of active ingredients in disinfectant - aldehyde - general uses

A
  • when require strong disinfection
  • antisepsis, sterilisation
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24
Q

types of active ingredients in disinfectant - aldehyde - disadvantages

A
  • toxicity (need PPE)
  • odour
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25
Q

types of active ingredients in disinfectant - aldehyde - types

A

1) paraformaldehyde: solid polymer, vaporised by heat for gaseous decontamination

2) glutaraldehyde: LAST RESORT

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26
Q

types of active ingredients in disinfectant - ortho-phthalaldehyde (OPA) - general

A

clear blue liquid, pH 7.5

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27
Q

types of active ingredients in disinfectant - ortho-phthalaldehyde (OPA) - MOA

A
  • OPA interact w amino acid, protein, microorganism
  • OPA less potent cross-linking agent but compensated for by lipophilic aromatic nature of OPA that assist uptake through outer layers of mycobacteria & gram -ve bacteria
  • kill spores by blocking spore germination process
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28
Q

types of active ingredients in disinfectant - ortho-phthalaldehyde (OPA) - advantages

A
  • stability over wide pH range (3-9)
  • X irritant to eyes and nasal passage
  • X odour
  • excellent material compatibility
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29
Q

types of active ingredients in disinfectant - ortho-phthalaldehyde (OPA) - disadvantages

A

handled with caution: stain proteins gray (including unprotected skin)

30
Q

types of active ingredients in disinfectant - biguanides - components

A

1) chlorhexidine
2) alexidine

31
Q

types of active ingredients in disinfectant - biguanides - chlorhexidine - general

A
  • broad spectrum bactericidal agent
  • activity pH dependent, greatly reduced in presence of organic matter
  • used in mouthwash
32
Q

types of active ingredients in disinfectant - biguanides - chlorhexidine - MOA

A

1) Damage membrane
2) cross cell outer membrane (passive diffusion)
3) Attacks:

  • bacterial cytoplasmic (coagulation, gelling)
  • inner membrane
  • yeast plasma membrane (partition into cell wall, plasma membrane, cytoplasm of cells)
33
Q

types of active ingredients in disinfectant - biguanides - alexidine

A
  • contain ethylhexyl end groups
  • faster onset of bactericidal activity
  • significantly faster alteration in bactericidal permeability
  • reduce lipid phase separation & domain
34
Q

types of active ingredients in disinfectant - chlorine - general

A
  • liquid (sodium hypochlorite), solid (calcium hypochlorite)
  • broad spectrum antimicrobial activity
35
Q

types of active ingredients in disinfectant - chloride - advantages

A

1) no toxic residues
2) cheap
3) fast acting
4) remove dried/fixed organisms & biofilms from surfaces
5) low incidence of serious toxicity
6) effective because works on different places of microorganisms

36
Q

types of active ingredients in disinfectant - chloride - MOA

A
  • attributed to undissociated hypochlorous acid (HOCI)
  • oxidation of sulfhydryl enzymes & amnio acid
  • ring chlorination of amino acids
  • loss of intracellular contents
  • decreased uptake of nutrients
  • inhibition of protein synthesis
  • decreased oxygen uptake
  • oxidation of respiratory components
  • decreased ATP production
  • DNA breaks
  • depressed DNA synthesis
37
Q

types of active ingredients in disinfectant - chloride - factors affecting efficacy

A
  • pH
    ** HOCL dissociate to less microbiocidal form
    ** increase pH = decrease efficacy
38
Q

types of active ingredients in disinfectant - chloride - disadvantages

A
  • household bleach cause ocular irritation, oropharyngeal/esophageal/gastric burn
  • corrosiveness to metal in high concentration
  • inactivation by organic matter
  • discolouring of fabrics
  • release of toxic chlorine gas when mixed w ammonia/acid (household cleaning agents)
  • relative stability
39
Q

types of active ingredients in disinfectant - chloride - alternative compounds

A
  • types:
    1) demand-release chlorine dioxide
    2) sodium dichloroisocyanurate
    3) chloramine-T
  • advantages
    1) retain chlorine longer = exert prolonged bactericidal effect
    2) sodium hychloroisocyanurate tablets stable & higher activity than sodium hypochlorite because more free chlorine available
40
Q

types of active ingredients in disinfectant - iodine - usage

A

antiseptic on skin/tissue

41
Q

types of active ingredients in disinfectant - iodine - MOA

A

penetrate cell wall of microorganism quickly = disrupt protein & nucleic acid structure & synthesis

42
Q

types of active ingredients in disinfectant - iodophor - general

A
  • iodine + solubilising agent/carrier
  • sustained-released reservoir of iodine
  • release small amount of free iodine in aq solution
43
Q

types of active ingredients in disinfectant - iodophor - advantages

A
  • non staining
  • free of toxicity & irritancy
44
Q

types of active ingredients in disinfectant - iodophor - usage

A

antiseptic & disinfectant

45
Q

types of active ingredients in disinfectant - iodophor - MOA

A

free iodine contribute to bactericidal activity

46
Q

types of active ingredients in disinfectant - iodophor - factors contributing to efficacy

A
  • dilute iodophor = more rapid bactericidal activity
  • potentially weaken iodine linkage to carrier polymer = increase in free iodine in solution
47
Q

types of active ingredients in disinfectant - peroxygens (h2o2) - uses

A
  • disinfection, sterilisation, antisepsis
  • broad spectrum efficacy against virus, bacteria, yeast, bacterial spore
  • high concentrations & longer contact time for sporicidal activity (increased efficacy in gaseous phase)
48
Q

types of active ingredients in disinfectant - peroxygens (h2o2) - general

A
  • greater activity against gram pos than neg
  • presence of catalase/other peroxidase in organisms increase tolerance
49
Q

types of active ingredients in disinfectant - peroxygens (h2o2) - advantages

A
  • environmentally friendly (Rapidly degrade into water and oxygen)
  • relatively stable + contain stabilisers to prevent decomposition
50
Q

types of active ingredients in disinfectant - peroxygens (h2o2) - MOA

A

oxidant
- produce free radicals (.OH)
- attack essential cell components

51
Q

types of active ingredients in disinfectant - peroxygens (h2o2) - alternatives

A

accelerated hydrogen peroxide

  • enhance bactericidal efficacy by:
    1) surfactant
    2) organic acid
    3) emulsifier acid
  • uses
    1) disinfectant/cleaning agent
  • stabilise h2o2 for extended use in med/vet device
52
Q

types of active ingredients in disinfectant - peracetic acid (CH3COOOH) - uses

A
  • more potent biocide than h2o2
  • sporicidal, bactericidal, virucidal, fungicidal at low conc
  • low temperature liquid sterilant for medical device, flexible scope, HD
  • environmental surface sterilant
53
Q

types of active ingredients in disinfectant - peracetic acid (CH3COOOH) - advantages

A
  • decompose to safe to use by products (Acetic acid & o2)
  • free from decomposition by peroxidases
  • remain active in presence of organic loads
54
Q

types of active ingredients in disinfectant - peracetic acid (CH3COOOH) - MOA

A
  • denature proteins & enzymes
  • increase cell wall permeability by disrupting sulfhydryl (-SH) & sulfur (S-S) bond
55
Q

types of active ingredients in disinfectant - phenol - uses

A
  • antiseptic, disinfectant, preservative
  • antifungal (Damage to plasma membrane)
  • antiviral (X effect on capsid unless treatment > 20 min)
56
Q

types of active ingredients in disinfectant - phenol - MOA

A
  • membrane-active properties
  • induce progressive leakage of intracellular constituents
    ** release of K+: first index of membrane damage
57
Q

types of active ingredients in disinfectant - chloroxylenol (halophenol) - uses

A
  • antiseptic
  • disinfectant formulation
  • bactericidal
    ** P. aeruginosa & many moulds highly resistant
  • excipient in topical products
58
Q

types of active ingredients in disinfectant - chloroxylenol (halophenol) - advantages

A
  • non toxic, non irritant
    ** but toxic upon oral consumption or eye contact
59
Q

types of active ingredients in disinfectant - diamidines - uses

A
  • anti bacteriostatic agent for topical treatment of wound
  • disinfection, antisepsis
60
Q

types of active ingredients in disinfectant - diamidines - MOA

A

inhibition of oxygen uptake & leakage of amino acid

61
Q

types of active ingredients in disinfectant - silver compounds - silver nitrate

A

1) uses

  • antimicrobial, antifungal

2) MOA

  • interaction w thiol in enzymes & proteins
  • affect microbial plasma, cytoplasmic membrane, nucleic acid
62
Q

types of active ingredients in disinfectant - diamidines - silver sulfadiazine

A

1) General

  • combination of 2 antibacterial agent & sulfadiazine
  • broader spectrum

2) MOA

  • induce membrane bleb in susceptible bacteria
63
Q

types of active ingredients in disinfectant - mercuric chloride (HgCl2) - uses

A

broad range disinfectant

64
Q

types of active ingredients in disinfectant - mercuric chloride (HgCl2) - MOA

A

affect microbial peptide synthesis

65
Q

types of active ingredients in disinfectant - mercuric chloride (HgCl2) - disadvantages

A

1) highly toxic both acutely & cumulative poison (AKI if accumulate in kidney)
2) corrosive

66
Q

types of active ingredients in disinfectant - quaternary ammonium compounds - uses

A

1) environmental sanitation of non critical surfaces (floor, wall, furniture)
2) fungicidal, bactericidal, virucidal against lipophilic (enveloped) viruses
3) X sporicidal, tuberculocidal, virucidal against hydrophilic (non-enveloped) viruses

67
Q

types of active ingredients in disinfectant - quaternary ammonium compounds - disadvantages

A

skin irritant

68
Q

types of active ingredients in disinfectant - quaternary ammonium compounds - MOA

A

1) adsorption & penetration into cell wall
2) Reaction w cytoplasmic membrane (lipid/protein) -> membrane disorganisation
3) leak of intracellular low MW material
4) degradation of proteins & nucleic acid
5) wall lysis caused by autolytic enzymes

69
Q

types of active ingredients in disinfectant - vapour-phase sterilant - uses

A

sterilise heat-sensitive medical devices & surfical supplies

70
Q

types of active ingredients in disinfectant - vapour-phase sterilant - types

A

1) Ethylene oxide, formaldehyde
2) hydrogen peroxide, peracetic acid

PR3151 CA1 (5 decks)

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