Flashcards in Introduction Deck (13):
What is an infection?
Invasion of a hosts tissue by micro-organism
Disease abused by:
What is the difference between infection and colonisation?
Infection involves the host responding badly, microbial multiplication and toxins.
Whereas, colonisation is when the microbes just live on us and don’t cause disease.
How do people get infection?
From themselves - eg if pneumonia goes from throat to lungs (when comatose) it will then cause disease.
Source - either via an intermediate or not
What is microbiota?
This describes micro-organisms carried on skin and costal surfaces.
Normally harmless or even beneficial - eg bacteria in colon produce vitamins
If these bacteria transfer to other sites then they can be harmful
How are infections spread?
Physical contact - eg STIs
Airborne spread may be sufficient for other infections eg chickenpox - droplet or aerosol.
Vector may be necessary eg mosquito for malaria.
Environment eg Food or Water - legonellea bacteria spread in water - causes. Legonairs disease (SPELLING?!)
E. Colli 0157 in gut of cows can contaminate dairy (or meat) - cause very dangerous infection.
What are the two types of transmission of disease?
-Contact (direct, indirect, vectors)
-mother to child, before or at birth
How do bacteria cause disease?
2. Adherence -to human surface
Inc. Virulence factors (produce by organism nd release into environment)
Host cellular dangers
What are virulence factors?
Exotoxins - cytolytic, AB toxins (PBL), superantigens, enzymes
Endotoxins - From the bacterial cell once dying
How does the virus cause host cellular damage?
This can be due to direct consequence of microorganism or host immune response.
-Consequent to host immune response
What are the 4 P’s of infection?
-site of infection
-co-morbidities eg diabetes makes them more likely to get an infection (E. coli)
How do we know patients have an infection? (What questions to answer?)
Is there an infection?
Where is the infection
What is the cause of the infection?
What is the best treatment?
How do we know if patients have an infection?