Infection Prevention & Control

Question 1

What are the stages involved in the chain of infection?

Answer 1

1. Pathogenic organism
2. Reservoir or source that allows organism to survive and multiply
3. Mode of exit from the source
4. Mode of transmission from the source to the host
5. Portal of entry through which the pathogen can enter the host
6. Susceptible (non-immune) host

Question 2

What is significant about the pathogenic organism involved in the chain of infection?

Answer 2

They must be of sufficient virulence and in adequate numbers to cause disease

Question 3

What is involved in infection prevention & control (IPC)?

Answer 3

Any activities undertaken with the aim of breaking the chain of infection

Question 4

By which methods may IPC be acheived?

Answer 4

• Eliminate the pathogenic organism
• remove the source / reservoir
• minimise transmission
• eliminate exit and entry
• reduce susceptibility to infection

Question 5

What actions can be taken to eliminate the pathogenic organism?

Answer 5

Environmental cleaning & decontamination:

• H₂O₂ room decontamination
• spillage management
• laundry

Equipment decontamination:

• sterilisation
• disinfection

Antisepsis:

• surgical skin prep
• MRSA decolonisation

Antibiotic prophylaxis:

• perioperative
• post-exposure

Question 6

What methods can be used to remove the source / reservoir?

Answer 6

• Hand hygiene
• environmental cleaning and decontamination

Question 7

What steps can be taken to try and minimise transmission?

Answer 7

Hand hygiene

Personal protective equipment (PPE):

• Aprons, gloves and masks

Equipment decontamination:

• surgical instruments
• stethoscopes, blood pressure monitors, USS probes, etc.

Use of disposable equipment:

• syringes, needles, etc.

source and protective isolation

Question 8

What are the 2 types of bacteria that everyone carries on their hands?

What are the difference in properties of these bacteria?

Answer 8

Resident bacteria:

• deep seated
• difficult to remove

Transient bacteria:

• easily picked up and transferred
• easily removed
• important cause of healthcare associated infections

Question 9

What are the 5 moments for hand hygiene at the point of care?

Answer 9

1. Before patient contact
2. Before a septic task
3. After body fluid exposure risk
4. After patient contact
5. After contact with patient surroundings

Question 10

When should soap and water be used?

When should alcohol gel be used?

Answer 10

Soap & water:

• for visibly soiled hands
• contact with particular infections e.g. C. Difficile, viral gastroenteritis

Alcohol gel:

• suitable for most activities that are likely to be undertaken when visiting clinical areas

Question 11

What is the definition of decontamination?

Answer 11

A combination of processes that removes or destroys contamination so that infectious agents or other contaminants cannot reach a susceptible site in sufficient quantities to initiate infection, or other harmful response

Question 12

What are the different decontamination methods?

Answer 12

1. Sterilisation
2. Disinfection
3. Antisepsis

Which method is appropriate / required depends on the situation

Question 13

What is involved in sterilisation?

When is it used?

Answer 13

This is the complete killing or removal of all types of micro-organisms

bacteria:

• vegetative - endowed with the power or faculty of growth
• spores - C. Tetani, difficile, perfringens

also for viruses, fungi and mycobacteria

Question 14

What are the 4 sterilisation methods used?

Answer 14

1. Heat - moist or dry
2. Chemical - gas or liquid
3. Filtration
4. Ionising radiation - used for single use disposable equipment

Question 15

How is sterilisation by moist and dry heat acheived?

Answer 15

Moist heat:

• autoclave
• involves delivery of steam under high pressure
• specific pressure and temperature cycles

Dry heat:

• oven
• acheived through controlled temperature cycles

Question 16

What is meant by “disinfection”?

Answer 16

The removal or destruction of sufficient numbers of potentially harmful micro-organisms to make an item safe to use

Question 17

What is meant by “antisepsis”?

Answer 17

Disinfection applied to damaged skin or living tissues

this requires a disinfectant with minimal toxicity

Question 18

How is disinfection acheived?

Answer 18

Almost always by the use of chemical disinfectants

Question 19

What properties of chemical disinfectants need to be considered?

Answer 19

Effects on microorganisms:

• antimicrobial spectrum
• sporicidality

Chemical properties:

• shelf life, in-use concentration, compatibility with other chemicals

Physical effects:

• corrosiveness

Harmful effects:

• irritant potential and toxicity

Question 20

What factors need to be considered when deciding which decontamination method to be used?

Answer 20

Risk of infection:

• high, medium or low

Physical properties:

• item
• packaging materials

Decontamination level:

• sterilisation, disinfection (antisepsis), cleaning, disposal

Question 21

What decontamination method should be used where possible?

Answer 21

Heat

this should be used where possible as it is the least hazardous method

Question 22

What is chemical disinfection limited to?

Answer 22

• Environmental decontamination - surfaces, spills, etc
• antisepsis
• heat-sensitive items

Question 23

In general, when should sterilisation, disinfection and cleaning be used as decontamination methods?

Answer 23

Sterilisation:

• items / devices that will enter sterile body areas or break the skin

Disinfection:

• items / devices that will contact mucous membranes or that will be contaminated with body fluids

Cleaning:

• items / devices that only contact intact skin (no body fluids)

Question 24

For surgical intstrument reprocessing, what is the risk of infection, decontamination level and method?

What physical properties must be considered?

Answer 24

Risk of infection:

• high

Physical properties:

• Metal construction
• paper / cloth packaging

Decontamination level:

• sterilisation

Decontamination method:

• moist heat

Question 25

For a flexible endoscope, what is the risk of infection, decontamination level and decontamination method?

What are the physical properties to consider?

Answer 25

Risk of infection:

• high

Physical properties:

• metal / plastic construction
• fragile, sensitive parts

Decontamination level:

• ​”high level” decontamination

Decontamination method:

• chemical

Question 26

for a syringe needle, what is the risk of infection and decontamination level and method?

What physical properties need to be considered?

Answer 26

Risk of infection:

• high

Physical properties:

• plastic / metal construction
• paper packaging

Decontamination level:

• sterilisation

Decontamination method:

• y-irradiation pre-use
• disposal after use

Question 27

What are the physical properties, decontamination level and method that should be used for a central venous catheter insertion site?

Answer 27

Physical properties:

• living tissue

Decontamination level:

• disinfection (antisepsis)

Decontamination method:

• chemical
• 2% chlorhexidine in 70% isopropyl alcohol