Week 4 - Healthcare infections and adaptive immunity Flashcards
1
Q
What are hospital acquired infections?
A
- Infections arising as a consequence of healthcare
- In hospital patients, it is neither present nor incubating at the time of admission
- – Onset is at least 48 hours after admission
- Includes infections in hospital visitors and healthcare workers
2
Q
What are some health care infection pathogens?
A
- Viruses: blood borne viruses (hep B, C, HIV), norovirus, influenza, chickenpox
- Bacteria: staph aureus (including MRSA), c.diff, e.coli, mycobacterium TB, klebsiella pneuomoniae, pseudomonas aeruginosa
- Fungi: candida albicans, aspergillus species
- Parasites: malaria
3
Q
What must you consider when looking at a person with a healthcare acquired infection?
A
- Extremities of age (premature babies have very few/no antibodies, elderly have a less active immune system)
- Obesity/malnourishment
- Smoking
- Diabetes
- Cancer
- Immunosuppression
- Emergency admission (increased risk of infection and poorer outcomes to infection)
- Surgical patient (already have a surgical site)
- Their interactions with:
- – Other patients
- – Healthcare workers
- – Visitors
- General and specific patient risk factors for infections
4
Q
What must you consider for ‘practice’ in a healthcare acquired infection?
A
- General and specific activities of healthcare workers
- – (e.g. hand hygiene, antibiotic prescribing, surgical technique)
- Policies and their implementation
- Organisational structure and engagement
- Regional and national political initiatives
- Leadership at all levels from government to the ward
5
Q
What are some patient interventions for infection control within a hospital?
A
General: - Optimise patient’s condition (e.g. stop smoking, improve diet, improve diabetic control) - Antimicrobial prophylaxis - Skin preparation - Hand hygiene Specific: - MRSA screens - Mupirocin nasal ointment - Disinfectant body wash Halting patient to patient transmission - Physical barriers: --- Isolation of infected patients --- Protection of susceptible patients
6
Q
What are some healthcare worker interventions for infection control within a hospital?
A
- Healthcare workers should be healthy
- – Disease free
- – Vaccinated
- Good practice:
- – Good clinical techniques
- – Hand hygiene
- – PPE
- – Antimicrobial prescribing
7
Q
What are some environment interventions for infection control within a hospital?
A
- Built environment (space/layout, toilets, wash basins)
- Furniture and furnishings
- Cleaning (steam cleaning, disinfectants, hydrogen peroxide vapour)
- Medical devices
- – Single use equipment
- – Sterilisation
- – Decontamination
- Appropriate kitchen and ward food facilities
- Good food hygiene practice
- Theatres
- Positive/negative pressure rooms
8
Q
What is personal protective equipment (PPE)?
A
- May include: gloves, mask, gown, shoe and head covers, face and eye protection
- They prevent contact with an infectious agent or body fluid that may contain an infectious agent
9
Q
Describe clostridium difficile symptoms, pathogenesis and treatment
A
- It causes antibiotic associated diarrhoea
- – Can lead to pseudomonas colitis
- Treat with oral vancomycin or metronidazole (antibiotics)
- Symptoms = watery diarrhoea, fever, loss of appetite, nausea, belly pain and tenderness
- The elderly and people with certain medical problems have the greatest chance of getting c. diff.
- C. diff. spores can live outside the human body for a very long time and may be found on things in the environment
- It can spread from person to person on contaminated equipment and on the hands of healthcare providers
10
Q
What diseases can staphylococcus aureus cause?
A
- Infections of skin and soft tissue
- Food poisoning
- Septicaemia
- MRSA (methicillin-resistant staphylococcus aureus
11
Q
Which antibiotics can be used to treat staphylococcus aureus diseases?
A
- Penicillinase resistant penicillin
- Flucloxacillin
12
Q
Describe norovirus
A
- ‘The winter sickness bug”
- Cause gastroenteritis
- Infection may be due to food poisoning, or by direct spread
- Typical symptoms = vomiting, nausea, watery diarrhoea, stomach cramps
13
Q
Where can antigen presenting cells be found?
A
- Skin
- Mucous membranes
- Lymphoid organs
- Blood circulation
14
Q
What are the different types of antigen presenting cells?
A
- Macrophages: found in various tissues, present to T cells
- Dendritic cells: found in the lymph nodes, mucous membranes and blood, present to T and B cells
- Langerhans cells: found in the skin, present to T cells
- B cells: found in lymphoid tissue, present to T cells
15
Q
What can antigen presenting cells detect?
A
- Extracellular pathogens (bacteria) → stimulates humoral immunity
- – So antibodies and complement proteins are released
- Intracellular pathogens (viruses) → stimulates cell-dependent immunity
- – So cytotoxic T cells, macrophages and antibodies are released
