Healthcare Acquired Infections, Diseases, Yr 3, Wk 1 Flashcards
What does HAI mean?
- Healthcare Associated Infection
- they are infections that were not present or in the pre-symptomatic phase at the time of admission to hospital
- which arise > or equal to 48 hrs after admission or within 48 hrs of discharge
List some 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
- Litigation (taking legal action)
- Loss of public confidence and decreased staff morale
Whats the a) most common cause of a HAI
b)What are the most common sites of HAI?
a) Proportion of HAIs are due to different infections
b) -UTI (22.6% of all HAI)- mainly related to catheterisation
- Surgical Site Infection (18.6%)
- Respiratory Tract Infection (17.5%)- intubation accounted for about 1/4 of these
- Bloodstream Infections (10.8%)- many central venous catheter (CVC) related
- Gastrointestinal infection (6.8% versus 15.4%)
- Skin and soft tissue infection (4.0%)
Give context to Bacteria versus Humans:
- Approx 10 to the power of 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
List some of Nature’s defence mechanisms (1st line of defence):
1st line of defence:
- Intact skin
- ‘Normal’ bacteria flora e.g. skin, GIT
- Body secretions e.g. tears containing antibodies/ enzymes, coughing
- Gastric Acid
- Flushing e.g. urination
List the body’s 2nd line of defence:
Immune system
Everyone and everything harbours microbes that may pose a risk…..Patients in hospital are……(finish this sentence)
…….Patients in hospital are more vulnerable to microbial colonisation AND infection
What is the fundamental question in clinical microbiology?
Colonisation versus Infection
Who discovered Staphylococcus aureus, (aka SA)?
Alexander Ogston
credited with introducing carbolic antiseptic spray to Aberdeen
What percentage of the population are colonised with SA in their nose (this includes patients, staff and relatives)?
30%
What type of SA are most people colonised with?
Most are colonised with the METICILLIN SENSITIVE Staphylococcus aureus (MSSA)
The same strain of Staphylococcus aureus can that is COLONISING can also cause INFECTION through:
- Break in skin e.g. surgical site infection
- Vascular device e.g. PVC, CVC
- Catheter associated urinary tract infection (CAUTI)
- Ventilator associated pneumonia (VAP)
Generally, what is the most common cause of a HAI?
Disturbance in bacterial-host equilibrium leads to most HAI
What are some factors related to MICROBIAL which tip the balance towards infection?
INCREASED:
-Resistance
- Virulence
- Transmissibility
- Increased survival ability
- Increased ability to evade host defences
What are some factors related to HOST which tip the balance towards infection?
- Devices: PVC, CVC, Urinary catheter, Ventilation
- Antibiotics
- Break in the skin surface
- Foreign body
- Immunosuppression
- Gastric Acid suppression
- Age extremes
- Overcrowding
- Increased opportunity for transmission e.g. Interventions, Hands !!
Number of bacteria required to cause infection if
a) No SILK SUTURE?
b) SILK SUTURE present?
(Silk suture is a surgical suture used to hold skin together)
a) 6.5 million bacteria
b) 100 bacteria
List some means of transmission microbes:
- Direct contact: e.g. SA, 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
List some ways of breaking the chain of infection:
- Risk awareness
- Standard Infection Prevention and Control Precautions (SICPs)
- Hand hygiene
- Appropriate PPE
- Vaccination
- Post exposure Prophylaxis
- Environment
Give the meaning of Cleaning:
Physical removal of organic material and decrease in microbial load
Give the meaning of Disinfection:
Large reduction in microbe numbers- spore may remain
Give the meaning of Sterilisation:
Removal/ Destruction of ALL microbes and spores
Cleaning, Disinfection, Sterilisation:
List some;
a) Low risk categories and how they should be treated:
b) Medium risk categories and how they should be treated:
c) High risk categories and how they should be treated:
a) Low risk: Intact skin contact e.g. stethoscopes, cots, Mattresses: Cleaning compatible with manufacturer’s instructions
b) Medium risk: Mucous membrane contact e.g. bedpans, vaginal specula, Endoscopes: Disinfection or sterilisation as appropriate
c) High risk e.g. surgical instruments: Sterilisation
Describe CLEANING and how it should be carried out:
- Manufacturer’s instructions
- Detergent and water
- DRYING IS AN IMPORTANT PART OF THE PROCESS!
- Cleaning essential PRIOR to disinfection and Sterilisation if these are required
Give 2 methods of Disinfection and describe them:
Heat:
- Pasteurisation (e.g. bedpans, linen, dishwashers)
- Boiling (vaginal specula, ear syringes)
Chemical:
- Chemicals vary in their organism activity range
- Needs to be equipment compatible
- Examples: Alcohol chlorhexidine, hypochlorites, hydrogen peroxide
(This is disinfection, NOT sterilisation)
