Healthcare Acquired Infections

Question 1

Define HAI

Answer 1

infections that were not present or in the presymptomatic phase at the time of admission to hospital, which arise >=48 hrs after admission or within 48hrs of discharge

Question 2

types of HAI

Answer 2

UTI
SSI
RTI
Blood stream infections
GI infections
Skin and soft tissue infections

Question 3

microbial factors leading to infection

Answer 3

increased resistance
virulence
transmissibility
increased survival ability
ability to evade host defences

Question 4

host factors leading to infection

Answer 4

o Devices: PVC, CVC, urinary catheter, ventilation
o Antibiotics
o Break in the skin surface
o Foreign body
o Immunosuppression
o ?gastric acid suppression
o Age extremes
o Overcrowding
o Increased opportunity for transmission – interventions – hands

Question 5

name the parts of the chain of infection

Answer 5

infectious agent
reservoir
portal of exit
means of transmission
portal of entry
susceptible host

Question 6

list ways of transmitting infections

Answer 6

1. Direct contact – staph a, coliforms
2. Respiratory/droplet – Neisseria meningitidis, mycobacterium tuberculosis
3. Faecal-oral – clostridium difficile, salmonella sp
4. Penetrating injury – group A streptococcus, BBVs

Question 7

name ways which you can break the change of infection

Answer 7

• Risk awareness
• Standard infection prevention and control precautions (SICPS)
• Hand hygiene
• Appropriate PPE
• Vaccination
• Post exposure prophylaxis
• Environment

Question 8

what is cleaning?

Answer 8

Cleaning is the physical removal or organic material and decreased in microbial load. Disinfection
results in a large reduction in microbe numbers but spores may remain. Sterilisation is the
removal/destruction of all microbes and spores.

Question 9

how should cleaning be carried out?

Answer 9

in accordance with the manufacturer’s instructions using detergent
and water. Drying is an important part of the process. Cleaning is essential prior to disinfection and
sterilisation.

Question 10

describe two ways of disinfecting things

Answer 10

Disinfection can be carried out using one of two methods. Heat can be used for the pasteurisation of
bedpans, linen and dishwashers. Boiling, also heat, can be used for vaginal specula and ear syringes.
Chemicals used for disinfection vary in their organism activity range. The equipment needs to be
compatible with the chemical. Chemicals include: alcohol, chlorhexidine, hypochlorites, and hydrogen
peroxide

Question 11

name 4 methods of sterilisation

Answer 11

1. Steam under pressure – autoclave
2. Hot air oven
3. Gas (Ethylene dioxide)
4. Ionising radiation

Question 12

define outbreak

Answer 12

2 or more cases of an infection linked in time and place

Question 13

name typing methods

Answer 13

• Antibiogram (antibiotic sensitivity pattern)
• Phage typing (e.g. staphylococcus aureus)
• Pyocin typing (pseudomonas)
• Serotypings (salmonella, pseudomonas)
• Molecular typing (DNA typing)

Question 14

what is the purpose of surveillance in infection?

Answer 14

detect and identify a possible outbreak at the earliest opportunity
act on suspicion

Question 15

control measures for outbreaks

Answer 15

1. Single room isolation
2. Cohorting of cases
3. Clinical area/ward closure
4. Re-enforcement of IPC measures
5. Staff exclusion
   a. E.g. colonised staff in case of MRSA, non-immune staff in case of VZV, measles etc
6. Staff decolonisation or other measur

Question 16

clinical features of c. diff infection

Answer 16

• Diarrhoea
• Faeces have a characteristic odour
• May have abdominal pain, pyrexia, raised white cell count
• Pseudomembranous colitis (PMC)

Question 17

c. diff is part of the normal flora in what % of adults?

Answer 17

2% up to 30% in the elderly

Question 18

what does c. diff have to do in order to cause disease?

Answer 18

produce two toxins

Question 19

for a diagnosis of c. diff to be made what must be present?

Answer 19

diarrhoeal symptoms