Lecture 8: Microbes and Disease Flashcards
Tuesday 22nd October 2024
What did Fracastoro say in 1546?
that invisible organisms cause disease
What did Leeuwenhoek discover in 1676?
‘animalcules’
What did Jenner discover in 1798?
The smallpox vaccination
What did Snow discover in 1849?
Epidemiology of cholera
When did Koch come up with his postulates? (linking pathogens to disease)
in 1884
Who discovered the chemotherapeutic agent for syphilis?
Ehrlich in 1910
When was Penicillin discovered and who by?
In 1929 by Fleming
Are the lungs normally sterile?
Yes
Is the urinary tract usually sterile?
Yes, except for the distal region of the uretha
what protects our gastrointestinal system from bacteria?
Normal flora
Is it true that all parts of our body have microbes?
Yes
Was it a surprise when researchers found that the respiratory tract was populated with bacteria deep into our lungs (and not just towards the top)?
Yes
Where are most microbes in the human body found?
In the gut
What does the lower respiratory tract include?
Trachea, Bronchi, Lungs (usually aren’t that highly populated with bacteria)
What happens if you have poor oral health?
Your teeth will be covered by film
Why do the levels of bacteria increase as you go down the body?
- community becomes more dynamic
- pH changes
Who first suggested the idea of the ‘human microbiome’?
Joshua Lederberg
What is the microbiome?
“the ecological community of commensal, symbiotic, and pathogenic microorganisms that literally share our body space”
What was the human microbiome project?
A US-funded project to assess the microbiome in 250 volunteers
What are the health benefits of the human microbiome?
- Preventing the attachment of bacteria to our epithelial cells
- Production of vitamins by bacteria (e.g. vitamin K in gut)
What problems are the microbiome associated with?
Obesity
Type 1 Diabetes
Crohn’s disease
Irritable bowel syndrome
Colon cancer
What do probiotics do?
They can help replenish benficial bacteria
What do prebiotics do?
They serve as a food source for beneficial bacteria in the gut
What allows for a bacteria to have virulence?
Adhesion to and entry into cells
Ability to turn off elements of the immune system
Production of toxins
What are conventional virulence factors?
- bacterial toxins
- adhesins
- cell surface carbohydrates and capsules
- secreted hydrolytic enzymes
- LPS
What are virulence factors usually encoded on ?
plasmids or through horizontal gene transfer, meaning pathogens can acquire these factors from other organisms, making non-pathogenic bacteria potentially dangerous under the right conditions.