Hygiene and disinfection

Question 1

What are examples of infectious agents?

Answer 1

bacteria
viruses
fungi
prions

Question 2

What is vegetative bacteria?

Answer 2

where bacteria grow and reproduce

Question 3

What is spore bacteria?

Answer 3

in a form of hybernation

Question 4

What are examples of spore bacteria?

Answer 4

clostridium and bacillus spp.

Question 5

What is the chain of infection?

Answer 5

Question 6

What is a bacterial infectious agent?

Answer 6

staphlococcus aureus

Question 7

What is the reservoir for S. aureus?

Answer 7

The nasal vestibule

Question 8

What is the portal of exit for S. aureus?

Answer 8

draining a wound

sneezing

Question 9

What is the portal of entry for S. aureus?

Answer 9

skin and intravascular devices

Question 10

mode of transmission of S. aureus?

Answer 10

contaminated hands

Question 11

Who is a susceptible host for S. aureus?

Answer 11

chronic conditions…

diabetes

cancer

eczema

lung disease

Question 12

What are the steps in the decontamination cycle?

Answer 12

Question 13

When is the decontamination cycle important?

Answer 13

for not single use items

Question 14

Decontamination definition

Answer 14

the combination of processes including cleaning, disinfection and/or sterilisation , used to render a re-usable item for further use

Question 15

What are the overall aims of decontamination?

Answer 15

1. make the item safe for staff to handle without presenting an infection hazard
2. make the item safe to use on a patient

Question 16

Cleaning definition

Answer 16

the process that physically removes soiling including large numbers of micro-organisms and the organic material on which they thrive

Question 17

Is there a standard methodology for cleaning procedure?

Answer 17

yes

Question 18

Disinfection definition

Answer 18

reduction i the number of viable micro-organisms on a product to a level previously specified as appropriate for its intended further handling or use

Question 19

What is a cidal effect of microorganisms?

Answer 19

killing of organisms

Question 20

What is a static effect on microorganisms?

Answer 20

reduction in reproduction of organisms

Question 21

What are disinfectants often?

Answer 21

chemicals

Question 22

What are the main ways chemicals can cause a static effect?

Answer 22

modification of proteins

Question 23

What are the main ways chemicals cause a cidal effect?

Answer 23

disruption of cell membrane

Question 24

What are example of chemicals causing a cidal effect by disruption of the cell membrane?

Answer 24

alcohol

detergents

phenol (rarely used)

Question 25

What are examples of chemicals causing a static effect by modification of proteins?

Answer 25

chlorine iodine heavy metals hydrogen peroxide formaldehyde string acids/alkalis

Question 26

What chemicals are used to modify the nucleic acids of bacteria?

Answer 26

dyes e.g. crystal violet

Question 27

Other than chemical disinfection, what else can be used?

Answer 27

thermal disinfection e.g. washer-disinfector

Question 28

What are the 3 things you should consider when carrying out the risk assessment of a disinfective agent?

Answer 28

toxicity shelf-life ease of use

Question 29

Sterile definition

Answer 29

the process to render a product sterile subject to a sterilisation process there is less than 1 in a million chance probability of a surviving organism

Question 30

What are the 4 methods of sterilisation?

Answer 30

heat chemical radiation filtration

Question 31

How does heat sterilise?

Answer 31

destruction of micro-organisms by denaturing proteins

Question 32

What are 3 types of heat sterilisation?

Answer 32

dry heat moist heat pasteurisation

Question 33

What is the most common type of heat sterilisation in dentistry?

Answer 33

moist heat

Question 34

What temperature is dry heat sterilisation carried out and for how long?

Answer 34

180 d.c. 2 hours

Question 35

What can sterilise at a lower temperature; moist or dry heat?

Answer 35

moist heat steam

Question 36

What is the most common form of moist heat sterilisation?

Answer 36

autoclave

Question 37

What should be carried out before autoclave sterilisation?

Answer 37

items must be cleaned rinsed dried

Question 38

Can instruments in an autoclave be touching?

Answer 38

no

Question 39

Wat are the 2 types of autoclave?

Answer 39

non-vacuum (type N) Vacuum (type B)

Question 40

How does the non-vacuum autoclave (Type N) sterilise?

Answer 40

bench top autoclave do not have a vacuum rely on gravity displacement instruments not wrapped up

Question 41

How does the vacuum autoclave (Type B) sterilise?

Answer 41

Forced air removal for porous loads and wrapped instruments.

Question 42

What is the advantage of a type B autoclave?

Answer 42

the instruments come out already wrapped

Question 43

What is the temperature, pressure and time required to safely sterilise dental equipment?

Answer 43

pressure: 2.25 bars temp: 134 d.c. time: 3 mins

Question 44

For some plastics/instruments, what is the alternative to autoclave sterilisation?

Answer 44

chemical gas ethylene oxide (most common) alkylates and nucleic acids UV x-rays filtration

Question 45

Can radiation be used for sterilisation?

Answer 45

yes

Question 46

Do spores need a higher dose of UV radiation for sterilisation?

Answer 46

yes x10 higher dose to kill spores

Question 47

What can X-ray sterilisation kill and not kill?

Answer 47

kill vegetative cells spores more resistant

Question 48

When would you use filtration for sterilisation?

Answer 48

useful for liquids such as IV infusion air in hospitals theatres

Question 49

What is used for filtration sterilisation?

Answer 49

membrane filter, different sizes depending on what microorganism you want to filter out

Question 50

What constitutes high risk category?

Answer 50

items which penetrate skin enter sterile body areas contact with severely ulcerated mucous membranes

Question 51

How would you decontaminate high risk category instruments?

Answer 51

sterilisation (autoclave, EO etc)

Question 52

What constitutes intermediate category?

Answer 52

contact with intact mucous membranes or non-intact skin

Question 53

How would you decontaminate intermediate risk instruments?

Answer 53

sterilisation/ disinfection (heat, chemical)

Question 54

What constitutes low risk category?

Answer 54

contact with intact skin or not in contact with patient

Question 55

How would you decontaminate low risk category instruments?

Answer 55

cleaning (general-purpose detergent)