MFD11 Flashcards
What are the 4 steps to Koch’s postulates
1) the candidate bacterium must be present in every case of disease ( must show bacterium in in a patient and not in a healthy patient)
2) Isolate bacterium from host, grow in pure culture.
3) Show that cultured bacterium causes same disease in a healhty subject (infect a subject X with candidate bacterium, observe that X becomes ill)
4) Isolate bacterium from experimental subject
Give 2 issues with carrying out koch’s postulates?
- If the bacteria cannot be grown in culture
- If no infecting organism can be detected
- If no suitable animal model is available
- If more than one species of bacterium is involved
- If it is the level rather than just the presence of the infecting bacterium that is important
Measuring Dysbiosis: Next Generation Sequencing
1) What has advances in DNA sequencing allowed the analysis of:
2) Targeted microbiome analysis typically involves sequencing the _______ gene for bacteria . WHY?
3) What do shotgun reads allow you to see?
1) detailed analyses of complex microbial populations
2) 16S rRNA gene (it is a very conserved area).
• OUT= oxonomic taxanomic unit, basically means species, only lets you look at bacteria
3) hat viruses are present as well.
What does Metagenomics involves?
sequencing all DNA present in a sample, then using bioinformatics to predict the source/function of the DNA sequences
Is the bacteria around the body all the same?
no depending on where you sample, has a big impact on which organisms are present
TRUE OR FALSE
Gut microbiome is one of the most diverse microbial communities in the body (>300 species/person).
true
What is commensal gut bacteria essential for?
healthy immune system
Which area of the body has a greater differences in microbial communities between people, mouth or gut?
gut
Differences in the microbiota between individuals are associated with:
(what conditions)
- Obesity
- Colorectal cancer
- Inflammatory bowel disease
- Many systemic conditions (though links are often less clear cut).
What were the observations made about the bacterial biomes present for patients with new-onset Paediatric Crohn’s Disease vs healthy patients:
All the bacteria decreased in the biome of those with Crohn’s have similar metabolic reactions, which means you are missing genes required for certain metabolic pathways.
What treatments target microbiomes?
1) Careful selection of antibiotics to minimise unwanted shifts in the microbiota.
2) Repopulation of the gut with healthy bacteria
What are the different methods of repopulation of the gut with healthy bacteria?
- Prebiotics (You really on the healthy bacteria being there still and you feed them)
- Probiotics (live yogurts, full of good bacteria- atm not regulated yogurt companies just feed you bacteria you don’t even know if it will reach the gut)
- Faecal microbiota transplantation (encouraging results for relapsing C. diff. infection but not so clear for IBD).= microbiome restored (sometimes)
Major dental plaque-related diseases:
2
- Dental caries
* Periodontitis.
What is the Specific plaque hypothesis:
diseases are caused by a single microorganism.
What is the Non-specific plaque hypothesis:
diseases are caused by the amount of plaque.
