Lecture 10 Microorganism And Disease Flashcards
What is mutualism
Beneficial associations
Example - bacteria providing vitamin precursors in gut
What is Commensalism
Passive associations
Example– non pathogenic Staphylococci
What is Parasitism
Microorganism causes harm
Example – pathogenic bacteria
What is Microbiology
The study of micro organisms
Example of good bacteria (Probiotics)
•Clostridium Butyricum
Produces important fatty acids
•Bifidobacteria
Modulates immune response and produces vitamins
•Lactobacilli
Produces vitamins and minerals , boost immunity and protects against carcinogens
Example of Bad bacteria
•Clostridium Difficile
Causes diarrhoea and abdominal pain
•Campylobacter
Also known as “food poisoning” it is found in uncooked chicken
•Enterococcus Faecalis
A common source of post surgical infection
How do we prove a pathogen
Koch’s Postulate
Explain Koch’s Postulate
1.The m/o must be present in the diseased and not in a healthy animal
2.M/O must be cultivated in pure culture
3.Pure culture inoculated into 2nd animal disease
4.Pure culture from 2nd animal should be same as 1st.
Exceptions to Koch’s Postulate
•Some pathogens difficult to culture.
•Some diseases are caused by combinations of
-Pathogens
-Physical, environmental
-Genetic factors
•Animal models and ethics: inoculation of healthy susceptible host not always possible (the postulate could never be fully applied to HIV)
Name the group of factors that can define host specificity
Virulence factors
What do Adhesions recognise
Specific receptors
Secretion of enzymes allows microorganisms to alter what
Their environment
What is Leukocidins used for
To destroy White blood cells (WBC)
What is Catalase used for
to protect from reactive oxygen species in the Macrophage
Some blood borne pathogens have the ability to secrete coagulase which leads to coagulation allowing microorganisms to
form clots which in turn can provide a physical hiding place from the immune system.
What do Cytotoxins do
kills or affects the functions of host cells
What do Neurotoxins do
Interferes with nerve cells
What do Enterotoxins do
affects cells lining gut tract
Example of Neurotoxins
•Clostridum botulinum
•Clostridium tetanii
secrete extremely potent neurotoxins which lead to two very different forms of fatal paralysis
Example of Enterotoxins
•Clostridium perfringens
secretes an enterotoxin which can induce gastroentertis on its own
Is a virulence or colonization factor directly involved in causing a disease
Virulence factor
What is a colonization factor necessary for
A disease to progress but is not directly involved
Where are Endotoxins primarily found
In Gram negative organism
Example of Colonization factors
•Adhesins
•Flagella
Both for motility
