Theme 3 Lecture 23: Infection Prevention and control

Question 1

Describe the cycle of infection

Answer 1

1. Pathogenic organism (of sufficient virulence and in adequate numbers to cause disease)
2. Reservoir (that allows organism to survive and multiply)
3. Exit (mode of exit from source)
4. Transmission (from source to host)
5. Entry (of pathogen into host)
6. Susceptible host (i.e non-immune)

Question 2

Explain the cycle of infection for MRSA

Answer 2

1. Pathogenic organism: MRSA
2. Reservoir: human skin particularly nose and other moist/hairy areas
3. Mode of transmission, exit and entry: direct contact with infected sites or indirect contact with fomites or hands of healthcare workers
4. Susceptible host: any breakdown in skin integrity

Question 3

What 3 situations define an outbreak?

Answer 3

• two or more linked cases of the same illness
• when the observed number of cases exceeds the expected number
• single case of disease caused by a specific pathogen

Question 4

Which viruses commonly cause outbreak in hospitals?

Answer 4

• influenza
• norovirus (“vomiting disease”)
• SARS CoV-2

Question 5

Which bacteria commonly cause outbreak in hospitals?

Answer 5

• C.difficile
• MRSA
• group A streptococcus
• VRE (vancomycin resistant enterococci)
• multi drug resistant gram -ves (ESBL, CPEs)

Question 6

which fungi commonly cause outbreaks in hospitals?

Answer 6

aspergillus

Question 7

How do we prevent the spread of MRSA?

Answer 7

1. Pre-operative screening +/- decolonisation

2. Perioperative antibiotics - with activity against MRSA if knownn positive

Question 8

Where are patients screened for MRSA?

Answer 8

Nose, axilla, groin

Question 9

What are some IPC techniques to minimise the spread of infections in surgery?

Answer 9

• surgical skin prep
• scrub technique and hand hygiene
• ventilation of operating theatre
• clinical waste
• environmental cleaning and decontamination
• sterilisation of equipment

Question 10

What is decontamination?

Answer 10

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 11

What is disinfection and what are the two main methods?

Answer 11

• disinfection reduces micro-organisms to a level at which they are not harmful
• two main methods are heat disinfection (e.g dishwasher) or chemical disinfection (e.f chlorine)

Question 12

What is cleaning?

Answer 12

removal of dirt, dust and any organic matter using water and detergent

Question 13

What is sterilisation?

Answer 13

destroys all micro-organisms including spores

Question 14

What are the methods of sterilisation?

Answer 14

1. Heat
   - moist: autoclave - delivery of steam under high pressures
   - dry: oven
2. Chemical
   - gas,liquid
3. Filtration
4. Ionising radiation
   - for single use disposable equipment

Question 15

Which is the least hazardous method of decontamination (and therefore should be used where possible)?

Answer 15

heat

Question 16

Which methods should be used for items/devices that will contact mucous membranes or that will be contaminated with body fluids?

Answer 16

disinfect

Question 17

Which methods should be used for items/devices that will enter sterile body areas or break the skin?

Answer 17

sterilise

Question 18

Which methods should be used for items/devices that only contact intact skin?

Answer 18

clean

Question 19

How would a blood pressure cuff be decontaminated?

Answer 19

cleaned only

Question 20

How would surgical instruments be decontaminated?

Answer 20

• sterilisation

- by mois heat

Question 21

How would the central venous catheter (CVC) insertion site be decontaminated?

Answer 21

• disinfected (antisepsis)

- by chemicals

Question 22

What are post-operative interventions for IPC?

Answer 22

• wound care
• hand hygiene
• PPE
• clinical waste disposed of
• decontamination of medical equipment
• environmental cleaning and decontamination
• patient placement - MRSA +ve patients should be nursed in a single room with en suite toilet facilities

Question 23

What two types of bacteria do we carry on our hands?

Answer 23

1. resident bacteria - deep seated, difficult to remove

2. transient bacteria - easily picked up, transferred, removed

Question 24

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

Answer 24

1. before patient contact
2. before aseptic task
3. after body fluid exposure risk
4. after patient contact
5. after contact with patient surroundings

Question 25

What is antisepsis?

Answer 25

disinfection applied to damaged skin or living tissues - it requires a disinfectant with minimal toxicity