Microbial Pathogens Flashcards
What are the 3 major microbial pathogens?
Bacteria, Viruses and Fungi.
Where are microorganisms usually found?
Human body tissue (skin)
What is virulence?
Measure of pathogenicity
What is colonisation?
Microbe growing in host regardless of harm.
What is infection?
Microbe growing in absence of something else.
What is a zoonotic disease?
Disease that can be passed on from an animal to a human.
Is the skin a good portal of entry for pathogens?
No, skin is very resistant.
Conditions of skin?
Dry, acidic, salty environment.
Name typical entry routes.
Respiratory & Gastrointestinal tract. Mucous membranes.
Parenteral (through skin breach)
Which type of bacteria are allowed through the respiratory tract?
Airbourne
Gastrointestinal?
Contaminated food/water.
How do bacteria attach themselves in the adherence step of pathogenesis?
Using their glycocalyx.
How does invasion occur?
- Produce enzymes to break down host tissue
- Slime layer defence mechanism
How is virulence measured?
Using LD50
What are virulence factors?
Production of chemicals that help progress colonization.
What is purpose of attenuation?
Useful for research into the effect of virulence factors
What is attenuation?
loss of virulence
Definition of an exotoxin?
protein secreted from pathogen
Definition of endotoxin?
toxin in cells that is released when cell disintegrates.
AB toxins
Suicide bomber toxin
Cytolytic toxin
Break cell membrane
Name steps in Pathogenesis
- Exposure
- Adherence
- Invasion
- Colonization/Growth
- Toxicity/Invasiveness
- Tissue damage/Disease
Which microorganism usually grows on human skin?
Skin flora
Name common pathogens that enter through the respiratory tract
- Tubercolosis
- Pertussis
- Pneumoniae
- Streptococcus
- Diptheriae
- Pneumophila
