Session 1 Flashcards
What two things are essential for an infection to occur?
- Microbe
- Host
What is an infection?
An invasion of a host’s tissues by microorganisms and disease caused by; microbial multiplication, toxins and a host response.
Describe how a patient can in effect ‘give themselves’ an infection?
Due to microbiota
- These are microorganisms carried on skin and mucosal surfaces
- Normally harmless or even beneficial
- Transfer to other sites can be harmful
- e.g. urinary tract infection
How do people get infections?
- Physical contact may be required
- Airborne spread may be sufficient
- Vector may be necessary
- Ingesting contaminated food/water
- Inhalation of contaminated air
- Contact with contaminated surfaces
What are the different modes of transmission?
- Horizontal transmission
- Vertical transmission
Horizontal transmission
- Contact (direct, indirect and vectors)
- Inhalation (droplets and aerosols)
- Ingestion (faecal oral route)
Vertical transmission
- Mother to child, before or after birth
How do microorganisms cause disease?
- Exposure
- Adherence
- Invasion
- Multiplication
- Dissemination
What are the two main categories of disease determinants?
- Pathogen
- Patient
Pathogen disease determinants
- Virulence factors
- Inoculum size
- Antimicrobial resistance
Patient disease determinants
- Site of infection
- Co-morbitites
How do we know patients have an infection?
- Take a history (symptoms and potential exposures)
- Examination
- Investigations
What are the two types of investigations you could do?
- Supportive
- Specific
Supportive investigations
These are trying to find out how unwell the patient is
- Full blood count
- CRP
- Blood chemistry - test liver and kidney function
- Imaging - X ray, ultrasound, MRI
- Histopathology
Specific investigations
Help identify the cause of the infection
- Include bacteriology and virology
