5. Healthcare-Associated Infection (HAI) Flashcards
What is the definition of Healthcare-Associated Infections (HAI’s)?
- Infections that were not present, or in the pre-symptomatic phase, at the time of admission to hospital
- Infections which arise more than 48 hours after admission or within 48 hours of discharge
How prevalent are Healthcare-Associated Infections (HAI’s)?
4.9% patients in Scotland in 2011
What are the possible outcomes of Healthcare-Associated Infections (HAI’s)?
- Extended length of stay, pain, discomfort, permanent disability, death
- Increased cost
- Litigation
- Loss of public confidence and decreased staff morale
What are the most common sites of Healthcare-Associated Infections (HAI’s)?
- Urinary Tract Infections (UTI’s) - 22.6% (catheterisation)
- Surgical Site Infection - 18.6%
- Respiratory Tract Infection - 17.5% (intubation = 1/4)
- Bloodstream Infections - 10.8% (Central Venous Catheter)
- Gastrointestinal Infection - 6.8%
- Skin and Soft Tissue Infection - 4.0%
What is natures 1st Line defence mechanisms against infections?
- Intact Skin
- Normal Bacterial Flora (Skin and G.I. Tract)
- Body Secretions (Coughing)
- Gastric Acid
- Flushing (Urination)
What is natures 2nd Line defence mechanisms against infections?
The immune system:
- Innate immune system
- Adaptive immune system
What, in the hospital setting, harbours mircrobes?
Everyone and Everything:
Patients in hosptial are more vulnerable to microbial colonization and infection
What is the difference between Colonisation and Infection, in relation to Staph Aureus?
Colonisation: Approx. 30% of the populous are colonised with Staph Aureus (most with Meticillin-Sensitive S.A.)
Infection: The same strain of Staph Aureus that is colonising can also cause infection through:
1. Breaks in the Skin (Surgical Site Infection)
2. Vasculature Device (PVC/CVC)
3. Catheter Associated UTI
4. Ventilator Associated Pneumonia (VAP)
What is the cause of most Healthcare-Associated Infections (HAI’s)?
Disturbance in the Bacterial-Host equilibrium
What Microbial factors tip the balance point towards infection?
- Increased Resistance
- Increased Virulence
- Increased Transmissability
- Increased Survival Ability
- Ability to Evade Host Defence’s
What Host factors tip the balance point towards infection?
- Invasive Devices (PVC, CVC, Urinary Catheter, Ventillation)
- Antibiotics
- Break in the Skin Surface
- Foreign Body (Silk Suture)
- Immunosuppression
- Gastric Acid Suppression
- Age Extremes
- Overcrowding
- Increased opportunity for transmission (e.g. interventions, hand hygiene)
What are the 3 phases of the Chain of Infection?
- Source of Microbe (Endogenous or Exogenous)
- Transmission
- Host
What are the means of Transmission for Healthcare-Associated Infections (HAI’s)?
- Direct Contact (Staph. Aureus, Coliforms)
- Respiratory / Droplet (N. Meningitidis, M. TB)
- Faecal - Oral (C. Diff, Salmonella sp.)
- Penetrating Injury (Group A Strep. BBV)
What ways are there to break the chain of infection?
- Risk Awareness
- Standard Infection Prevention and Control Precautions
- Hand Hygiene
- Appropriate PPE
- Vaccination
- Post-Exposure Prophylaxis
- Environment
What is the definition of cleaning?
Physical removal of organic material and decrease in microbial load
What is the definition of disinfection?
Large reduction in microbe numbers - spores may remain
What is the definition of sterilisation?
Removal / Destruction of all microbes and spores
When is cleaning appropriate?
With low risk procedures (Intact skin contact), cleaning (compatible with manufacturer’s instructions) is appropriate
When is disinfection appropriate?
With medium risk procedures (Mucous Membrane contact), disinfection is appropriate
When is sterilisation appropriate?
With high risk procedures (Surgical interventions)
What is used in cleaning?
Detergent and Water
Note - Drying is an important part of the process
Note - Cleaning is essential PRIOR to disinfection and Sterilisation, if these are required
What are the methods of disinfection?
- Heat - Pasteurisation, Boiling
- Chemical - Alcohol, Chlorhexidine, Hypochlorites, Hydrogen Peroxide
- Steam under Pressure
- Hot Air Oven
- Gas (Ethylene Dioxide)
- Ionising Radiation
What are the 2 types of Surveillance?
- Local Surveillance
- a) Laboratory Based
- b) Ward / Clinical Area Based
- National Surveillance
What is the function of Laboratory Surveillance?
Laboratory detects an organism and notifies IPCT and clinicians
What are the advantages of Laboratory Surveillance?
They know what organism is specific recommendations can be made
What are the disadvantages of Laboratory Surveillance?
- Depends on samples being sent
- Time taken to detect organism
- Tests not 100% accurate
What is the function of Clinical Area Based Surveillance?
Clinical Area staff notify the Infection Prevention and Control Team
What are the advantages of Clinical Area Based Surveillance?
- Detect potential problem sooner
2. Can ensure correct samples sent
What are the disadvantages of Clinical Area Based Surveillance?
- Causative microbe not known
2. IPC measures need to be more general
What are the Mandatory National Surveillance Reporting for Scotland?
- MRSA Bacteraemia
- MSSA Bacteraemia
- C. Diff
- Surgical Site Infection
- E.Coli Bacteraemia
What is the definition of an outbreak?
An outbreak of an infection is defined as 2 or more cases of an infection linked in time and place
What is necessary to determine if the strain is present (i.e. an outbreak)?
Typing via:
- Antiobiogram (Antibiotic sensitivity pattern)
- Phage typing (Staph. Aureus)
- Pyocin typing (Pseudomonas)
- Serotyping (Salmonella, Pseudomonas)
- Molecular typing (DNA typing)
What are the Control Measures of Outbreaks?
- Single Room Isolation
- Cohorting Cases
- Clinical Area / Ward Closure
- Re-inforcement of IPC measures
- Staff exclusions (infected/at risk)
- Staff decolonization or other measures
