Lecture 15 - Microbiome 2 Flashcards Preview

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Flashcards in Lecture 15 - Microbiome 2 Deck (44):
1

Compare the microbiota between individuals

Different individuals will have the same phyla present, but different species

2

To which infections does dysbiosis lead?

Salmonella

Overgrowth of:
- Candida
- Clostridium difficile

3

Which bacterium is responsible for Pseudomembranous colitis?

Clostridium difficile

4

Are many people infected with Clostridium difficile?

3%

5

Describe how Clostridium difficile can overgrow

1. Gut microbiota altered (antibiotics)
2. Reduced competition, C. difficile overgrow
3. Cytotoxin toxin produced
4. Cell death, inflammation and bowel necrosis

6

Which people are most likely to get Pseudomembranous colitis?
Where do outbreaks normally occur?

People taking antibiotics

Outbreaks are common in hospitals, where people are taking antibiotics

7

Describe the gut microbiota of individuals who get recurrent C. difficile infections

Reduced diversity of gut microbiota

(compared to people who get single infections / no infections

8

How can normal gut microbiota be reinstated in people with recurrent C. difficile infections?

Faecal transplant

9

What must we do before we give someone a faecal transplant?
Why?

Rationally select the bacteria in the transplant, so we know what we are giving the other people

This is so the recipient doesn't receive unknown pathogens that could cause disease

10

How may else may gut microbiota cause disease?

Moving to extra-intestinal sites:
- wounds
- respiratory tract
- urinary tract
- blood

11

In what circumstances will gut microflora cause infection of other sites?

Abnormal host:
- anatomical
- functional
- immunocompromised

12

Which gut microflora causes UTIs?

E. coli

13

Which microflora causes wound infection?

Klebsiella
Bacteroides sp.

14

Which microflora bacterium causes Lower Respiratory tract infection?

Klebsiella

15

Intestinal microbiota are a rich source of ...

DNA

16

Why is the gut microbiota important for immunity?

Microbial colonisation is linked with development of the immune response, through the differentiation of Treg

17

Describe the importance of gut microflora on asthma and allergies

Reduced incidence when mother is exposed to animals

18

Children who develop atopy have a higher incidence of ...

Clostridia compared to non-atopic children

19

What is the connection between caesarian sections and disease?

Children who were delivered by C section are 20% more likely to have asthma

20

Which diseases are associated with abnormal gut microbiota?

- Asthma
- Allergies
- Eczema
- Inflammatory bowel disease
- C. difficile - Pseudomembranous colitis

21

What is inflammatory bowel disease associated with?

- Inappropriate immune response against intestinal microflora

- Reduced diversity

22

What happens to intestinal permeability in patients with IBD?

Increased intestinal permeability

23

What are prebiotics?

These are dietary supplements that promote beneficial bacteria

24

What are probiotics?

Doses of beneficial bacteria in the diet

25

Which bacteria are commonly administered as probiotics?

Lactobacillus sp.

26

What do probiotics supposedly protect against?

- Rotavirus
- Childhood diarrhoea
- Atopic eczema

27

What are the three general things that affect the immune system?

- Nutrients
- Infection with enteropathogens
- Gut microbiota

28

Describe how the diet affects microbiota in the gut

Varying the levels of protein, monosaccharides, polysaccharides and lipids changes the numbers and types of bacteria in the gut

29

How does microbiota affect the metabolism?

How?

Without microbiota, a higher energy intake is required.

- Directly provide nutrients (Vik K, biotin, folate CHO from cellulose)

- Alter metabolic machinery of host cells

30

Describe how differences in microbiota in a population affects metabolism of the population

Despite differences in microbiota, the individuals had stable metabolic pathways

31

Obesity / high fat diet is associated with an increase in which phyla?

What about decrease?

In general?

In general:
decreased diversity of microbiota

Increase:
- Firmicutes
- Actinomycetes

Decrease:
- Bacteroides

32

What is the role of actinomycetes in obesity?

This phlum enriches metabolic pathways associated with obesity
--> increased capacity for energy harvest

33

What happens to the inflammatory response in high fat diets?

Increased inflammatory responses

34

What is the effect of 'obesity' microbiota on the brain?

Decreased satiety

35

What is the effect of 'obesity' microbiota on the liver?

Increased SCFAs
Increased inflammation

36

What is the effect of 'obesity' microbiota on the adipose tissue?

Increased Triglyceride incorporation

37

What is the effect of 'obesity' microbiota on muscle?

Decreased fatty acid oxidation

38

What is the effect of 'obesity' microbiota on the GIT epithelium?

Increased permeability

39

In general, what is the role of gut microbiota in malnutrition?

Malnutrition at a young age seems to permanently affect the make up of the microbiota in the gut

40

What was the conclusion from the Kwashiokor study?

The gut microbiota was responsible for propagating the severe and acute undernutrition

41

Describe the results of the study?

- Malawian twins; one fed well, one poorly
- Intervention: both given theraputic food
- Both twins had an increase in variability whilst on the food
- After food was removed, only the previously healthy twin maintained the variability of the microbiota

42

What did a switching of diet bring about in mice?

Rapid change in the diversity of the microbiota

43

What happens to the metabolism of mice with Kwashiorkor microbiota?

How?

Reduced TCA cycle

A product from the microbiota inhibits enzymes in this cycle

44

What is inflammatory bowel disease?

A general name for diseases such as:
• Crohn's disease
• Ulcerative colitis