sterilisation and disinfection

Question 1

cross-infection

Answer 1

staff&patients in a clinical setting

Question 2

sterilisation

Answer 2

kill/remove all living organisms, including endospores

Question 3

disinfection

Answer 3

kill/remove the majority of the organisms but not endospores

Question 4

antisepsis

Answer 4

kill/inhibit the organisms grow

Question 5

microbial death scale

Answer 5

exponential or logarithmic (not linear)

Question 6

rate of death depend on

Answer 6

1. initial population size;2.duration of exposure（time）
2. antimicrobial concentration;4.presentce of organic matter,,slia-mucosa,blood,
3. organism:morphological,cell wall structure,efflux of disinfectants /antiseptic

Question 7

mycobacterium tuberculosis less susceptible

Answer 7

cell wall structure( waxy, lipid-rich)

Question 8

psudomonas aeruginosa less susceptible

Answer 8

efflux pump

Question 9

sterilisation(4 stage)

Answer 9

1. presterilisation cleaning
2. packaging
3. sterilisation process
4. aseptic storage

Question 10

stage 1(sterilisation) method

Answer 10

1. manual scrubbing

2. automated cleaning(sonicator, instrument cleaner)

Question 11

method of sterilisation(stage 3)

Answer 11

1. hosptials: moist heat(autoclave), dry heat(hot air oven), chemical vapour/high temp(chemiclave)
2. commercially:chemical vapour/low temp(gas sterilisation）；radiation; membrane filtration

Question 12

autoclave how

Answer 12

high temperature and pressure destroy:cell membranes,proteins, nucleic acids

Question 13

autoclave depend on

Answer 13

1.holding time(

Question 14

autoclave cycle time

Answer 14

heating(pressurization);holding;cooling(depressurisation)

Question 15

dry heat sterilisation( hot air oven) how

Answer 15

membranes, bilogical molecules(protein and nucleic acids)

Question 16

dry heat use for

Answer 16

items damaged/ impenetrably by moist heat(powders,sharp instruments)

Question 17

chemiclave sterilization use

Answer 17

toxin gases. high tem&pressure

Question 18

plasticware,syinge,sutures catheters sterilization way

Answer 18

gas sterilisation: chemial vapour combined with low temperature

Question 19

uv does not penetrate

Answer 19

glass water other substances

Question 20

uv use to sterilise

Answer 20

internal cavity of laminar flow cabinets

Question 21

ionising radiation use

Answer 21

y-radiation(high energy)

Question 22

ionising radiation destory

Answer 22

change biological molecules

1. breakH-bonds
2. oxidises double bonds
3. destroys ring structures
4. polymerises some molecules

Question 23

ionising radiation use to

Answer 23

plastics, pharmaceuticals(antibiotics, hormones)

Question 24

membrane filtration

Answer 24

heat-sensitive pharmaceuticals(antibiotic solutions

culture media

Question 25

chlorhexidine

Answer 25

low -level disinfectants

Question 26

quaternary ammonium compounds

Answer 26

low-level disinfectants

Question 27

Chlorhexidine&quanternary ammonium compunds disadvantage

Answer 27

inactived by hard water&soap

Question 28

intermediate-level disinfectants

Answer 28

alcohols(70%),
halogen compounds
phenolics

Question 29

cell-membrane disinfectants

Answer 29

chlorhexidine,quanternary ammonium compounds

alcohol,phenolics,

Question 30

high-level disinfectants

Answer 30

aldehydes