health care associated infection

Question 1

definitions

Answer 1

infections that were not present or in the pre-symptomatic phase at the time of admission to hospital
which arise > 48 hrs after admission or within 48 hrs of discharge.

Question 2

Common causes

Answer 2

UTI- mainly related with catherisation
surgical site infection
blood stream infection-central venous catheter related
gastrointestinal infection
skin and soft tissue infect
microbial factors
increased-
resistance, virulence, ability to transmit
survival ability
evade host defense

Question 3

host factors

Answer 3

devices: catheter
antibiotics
breaks in skin surface
foreign body
immunosuppresion
gastric acid suppresion
overcrowding

Question 4

chain of infection

Answer 4

modes of transmission
-direct contact
eg staph aureus
respiratory/droplet
eg neisseria meningitidis
-Faecal oral
C diff
penetrating injury
-group A streptococcus

breaking chain of infection
\:risk awareness
standard infection prevention and control precautions
hand hygiene, appropriate PPE
vaccination
post exposure prophylaxis

Question 5

cleaning, disinfection, sterilisation

Answer 5

Cleaning:physical removal of organic material and decrease microbial load
o Used for Low risk items
♣ Intact skin contact e.g. stethoscopes, cots, mattresses
disinfection: large reduction in microbenumbers, spores may remain
o Medium risk
♣ Mucous membrane contact e.g. bedpans, vaginal specula, endoscopes
o Heat
♣ Pasteurisation (e.g. bedpans, linen, dishwashers)
♣ Boiling (vaginal specula, ear syringes)
o Chemical
♣ Chemicals vary in their organism activity range
♣ Needs to be equipment compatible
♣ Examples: Alcohol, chlorhexidine, hypochlorites, hydrogen peroxide

sterilisation: removal/ destruction of all microbes and spores
-surgical equipment
steam underpressure
hot air oven
ionising radiation

Question 6

surveillance

Answer 6

•	Local Surveillance:
o	Laboratory Based
♣	Laboratory detects an organism and notifies IPCT and clinicians
o	Ward/Clinical Area Based
♣	Clinical area staff notify Infection Prevention and Control Team (IPCT) – if potential outbreak
•	Ensures correct samples sent to lab 
•	Causative microbe not known
•	IPC measures need to be more general
National surveillance

Question 7

outbreak of an infection

Answer 7

2 or more cases of an infection linked in time and place.
Typing necessary to determine if the same strain present.
• Typing methods:
o Antiobiogram (antibiotic sensitivity pattern)
o Phage typing (e.g. Staphylococcus aureus)
o Pyocin typing (Pseudomonas)
o Serotyping (Salmonella, Pseudomonas)
o Molecular typing (DNA typing)