Module 6

Question 1

Prevention generally involves

Answer 1

Good hygiene practices

Application of disinfections

Question 2

2 important Approaches to prevention of infections in healthcare settings

Answer 2

Removal of microorganisms from the environment
(does not require sterilisation)

Removal of organisms from patient care equipment
(sterilisation)

Question 3

Difference between Cleaning and disinfection

Answer 3

Cleaning is the mechanical removal of a material from surfaces or objects

Disinfection is the destruction of most/all pathogenic microorganisms from an object

Question 4

Decontamination

Answer 4

Physical or chemical means to remove, inactivate or destroy microorganisms off a surface, so that it is safe to use

Question 5

Disinfection

Answer 5

Destruction of pathogens and other microorganisms by physical or chemical means (to an acceptable level)

However this does not kill endospores or some viruses

Question 6

Sanitisation

Answer 6

Cleaning an object to removal most microrganism

Question 7

Sterilisation

Answer 7

complete removal of all microorganism. This includes endospores and viruses

Question 8

Biocidal Chemicals to prevent microbial Growth

Answer 8

A poisonous substance, such as pesticide

Is not instant, and required TIME to work
(exponential killing curve)

Effectiveness depends on, the standardised procedures and the type of microorganism present

Question 9

At what heat confirms sterilisation

Answer 9

heat at 121’C for 30min

This is because some endospores can survive in heats past 100’C for several min.

Question 10

Why is Time and Concentration Important Factors

Answer 10

Time is required, as it kills exponentially over time

Concentration is important as too low of a concentration can lead to microorganisms withstanding the substance and too high concentrations as it can behave differently to the intended method of killing

Question 11

Why is Ethanol optimal between 60-90% but not higher or lower?

Answer 11

Below, its not enough to kill effectively and the disinfection rate drops dramatically

Above this There is not enough water in the solution, which acts as a catalyst and helps in denaturing proteins and vegetative cells. Also proteins coagulate instantly instead of denaturing which acts as a protective coat.

Question 12

3 factors for effective Disinfection/Sterilisation

Answer 12

Appropriate Biocidal Agent

Effective Contact

Sufficient Exposure (time and concentration)

Question 13

3 levels of risk for sterilisation and disinfection

Answer 13

Critical (Sterilisation)
for equipment that penetrates into tissue, body cavity or bloodstream

Semi-critical (single-use, sterilisation, high level disinfection)
For non intact skin or mucosal membrane

Non-critical (Cleaning)
Contact with intact skin only

Question 14

Cleaning

Answer 14

Most appropriate for inanimate objects

Ensures removal of organic material before disinfecting or sterilising

Question 15

what objects should not be used for Steam steriliser, Dry Heat, Incineration, Filtration

Answer 15

Steam sterilisers - Do not use for Heat sensitive

Dry Heat at 180 for 1 hour or 160 to 2 hours
- Do not use for heat sensitive materials

Incineration - non reusable equipment only

Filtration - Good for heat sensitive

Question 16

Moist Heat sterilisation

Answer 16

Autoclave (kills vegetative bacterial cells, including endospores and viruses)
- Good for most things

Boiling
- Temp of 121’C for 15min
15min is from the point when steam penetrates all parts of the object

Question 17

4 stages of Sterilising Cycle

Answer 17

Removal of air, admission of heat, and heating of the chamber to the sterilising temperature

Sterilisation time

• Penetration time
• Holding time

Removal of steam and drying the load

Restoration of atmospheric conditions

Question 18

Dry Heat sterilisation

Answer 18

Temperature of 180’C for 1 hours
160’C for 2 hours

Good for glass and some metal objects and reusable equipment in heatproof containers

Not good for fabrics and wrapping material

Question 19

Radiation

Answer 19

Ionising radiation damages or kills by causing disruption to DNA

Good for heat-sensitive organic material

Question 20

Filtration

Answer 20

Removal of microorganism form liquids or gases

Passage through a filter with small pores

Question 21

Heat Disinfection

Answer 21

Boiling water at 100’C for 5min is effect against most bacteria

Thermal disinfection is calibrated and standardised
60'C for 100min
70'C for 30min
80'C for 10min
90'C for 1min

Question 22

Pasteurisation Disinfection

Answer 22

63’C for 30min

Question 23

UV radiation Disinfection

Answer 23

DNA absorbs the radiation and causes nucleic acid to break, interfering with DNA and cell replication

Question 24

Filtration Disinfection

Answer 24

HEPA filter