Healthcare Acquired Infections Flashcards
What is a healthcare acquired infection?
- 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
What are the possible outcomes of HAI?
- Extended length of stay, pain, discomfort, permanent disability, death
- Increased Cost: 33% decrease in HAI in Scotland would lead to savings of £55 million (2007 National Prevalence Study)
- Litigation
- Loss of public confidence and decreased staff morale
What are the most common sites of HAI?
- UTI (related to catheterisation)
- Surgical site infection
- RTI (intubation)
- Bloodstream infections (central venous catheters)
- GI infection
- Skin and soft tissue infections
What is the relationship between humans and bacteria?
- Approx. 10^14 bacteria in adult human
- Approx 10 bacterial cells to every human cell
- Human beings carry >1kg of bacteria in their gut alone
- 500 different species of bacteria have been isolated from human stool
What are patients in hospital more vulnerable to?
Microbial colonisation and infection
What is the most common form of staph aureus to be colonised with?
Meticillin sensitive staphylococcus aureus (MSSA)
How can a colonising staph aureaus cause infection?
- Break in skin e.g. surgical site infection
- Vascular device e.g. PVC, CVC
- Catheter associated urinary tract infection (CAUTI)
- Ventilator associated pneumonia (VAP)
What process leads to most HAI?
A disturbance in the bacterial-host equilibrium
What microbial factors can tip the bacterial-host balance towards infection?
Increased
- Resistance
- Virulence
- Transmissability
- Increased survival ability
- Ability to evade host defences
What host factors can tip the bacterial-host balance towards infection?
- Devices: PVC, CVC, Urinary catheter, Ventilation
- Antibiotics
- Break in skin surface
- Foreign body
- Immunosuppression
- ?Gastric acid suppression
- Age extremes
- Overcrowding
- Increased opportunity for transmission e.g. Interventions, Hands!!!
What is required for chain of infection?
- Source of microbe (endogenous or exogenous)
- Transmission
- Host
What means of transmission are there for infection?
Direct contact
-e.g. Staphylococcus aureus, coliforms
Respiratory/Droplet
-e.g. Neisseria meningitidis, Mycobacteria tuberculosis
Faecal-Oral
-e.g. Clostridium difficile, Salmonella sp.
Penetrating Injury
-e.g. Group A streptococcus, Bloodborne viruses
How can the chain of infection be broken?
- Risk awareness
- Standard Infection Prevention and Control Precautions (SICPs)
- Hand Hygiene
- Appropriate PPE
- Vaccination
- Post Exposure Prophylaxis
- Environment
Cleaning
Physical removal of organic material and decrease in microbial load
Disinfection
Large reduction in microbe numbers-spores may remain
Sterilisation
Removal/destruction of ALL microbes and spores