The Microbiota of the GI Tract 2

Question 1

What are some factors that affects the gut microbiota?

Answer 1

Environment

Diet

Life stage

Disease

Faecal transplant

Prebiotics

Antibiotics

Probiotics

Question 2

Is microbial dysbiosis (imbalance) a cause or consequence of disease?

Answer 2

It is still unknown

Question 3

What are examples of diseases that can be caused by microbes that normally live asymptomatically in the host?

Answer 3

MRSA infection

Strep throat

Gingivitis

Acne

Meningitis

Pneumonia

C. Difficile diarrhoea

Thurst

Urinary tract infections

Gastric cancer

Question 4

What is an example of a disease that can occur when gut microbes translocate to other body sites?

Answer 4

Sepsis

Question 5

Where can gut bacterium often translocate to?

Answer 5

Bloodstream

Question 6

How has the incidence of infectious and immune diseases changed over the last 70 years?

Answer 6

Infectious diseases have been declining

Immune diseases have been increasing

Question 7

Why has the incidence of infectious disease declined over the last 70 years?

Answer 7

Better disease treatment

Vaccination

Health standards

Question 8

What has the incidence of immune diseases rised in the last 70 years?

Answer 8

Diet

Hygiene

Effect on microbiota possibly

Question 9

What does inflammation in IBD result due to?

Answer 9

Dysregulated host immune response to the gut microbiota

Question 10

How is the gut bacterial diversity different for people with IBD?

Answer 10

Less diverse than people who do not have IBD

Question 11

What does it mean that IBD typically manifests in a non-uniform manner?

Answer 11

Patients have regions of healthy tissue adjacent to inflammed regions

Question 12

What is an example of a bacterium that is elevated in Crohn’s disease?

Answer 12

Enterobacteriaceae

Question 13

Why is it very difficult to entangle cause from effect?

Answer 13

Many features of IBD itself could affect the microbiota, such as antibiotic use, inflammation, diarrhoea (affects transit time), host diet and host genotype

Question 14

What can reduced bacterial diversity and increase in Enterobacteriaceae occur due to?

Answer 14

Broad spectrum antibiotic use

Inflammation

Question 15

What impact does antibiotics have on the gut microbiota?

Answer 15

Decreases diversity and increases Enterobacteriaceae

Question 16

How does inflammation change the gut microbiota?

Answer 16

Question 17

How does diarrhoea alter the gut microbiota?

Answer 17

Decreased transit time alters microbial composition

Question 18

How does the hosts diet alter the gut microbiota?

Answer 18

Less fibre causes changes to microbiota composition

Question 19

What is currently being research in terms of the contents of the gut microbiota?

Answer 19

Manipulating the microbioa to redress the dysbosis and relieve symptoms of IBD

Question 20

How can the microbiota of the gut possible be manipulated to fix a reduction in Faecalibacterium prausnitzii numbers?

Answer 20

Provide specific prebiotics designed to boost numbers of F. Praesnitzii

Design F. Praesnitzii as a biotherapeutic agent

Question 21

How can the microbiota of the gut possible be manipulated to fix an increase in Enterobacteriaceae numbers?

Answer 21

Reduce antibiotic use to prevent decline in commensals

Question 22

What, and how, do the two main species of bacteria change in IBD?

Answer 22

Faecalibacterium prausnitzii decreases

Enterobacteriaceae increases

Question 23

What can be changed in someones diet to increase bacterial diversity?

Answer 23

Increase fibre

Question 24

What does the success of existing probiotics/prebiotics depend on?

Answer 24

Specific strain

Question 25

What is a probiotic?

Answer 25

Live microorganism which, when administered in adequate amounts confer a health benefit on the host (basically add live bacteria)

Question 26

What is a prebiotic?

Answer 26

A substrate that is selectively utilised by host microorganisms conferring a health benefit (basically food for resident bacteria)

Question 27

What are the conclusions of most studies that look at the effectiveness of probiotics?

Answer 27

They are beneficial in treatment and prevention of GI diseases

Question 28

What are the different mechanisms of action for probiotics?

Answer 28

Question 29

Do probiotics become permanent residents in the gut?

Answer 29

No, but their products and actions can still be beneficial under certain circumstances

Question 30

Why is the species and strain important when selecting probiotics?

Answer 30

Different species (even strains) have different effects Individual response varies due to existing variation in microbiota

Question 31

What are examples of prebiotics?

Answer 31

Question 32

What are the health benefits of prebiotics?

Answer 32

Improved gut function Management of inflammatory bowel disease May reduce risk of colon cancer GOS/FOS supplementation of infant formula increased bifidobacteria numbers FOS/insulin increase calcium absorption and bone health Consumption of prebiotics instead of sugards can lower glycaemic index

Question 33

How do prebiotics improve gut function?

Answer 33

Stook bulking and faster gut transit

Question 34

How do prebiotics reduce the risk of colon cancer?

Answer 34

Reduced DNA damage and cell proliferation Faster gut transit time

Question 35

What has banned the use of the words probiotic and prebiotic?

Answer 35

Current European Food Safety Authority (EFSA) regulations

Question 36

What are some permitted health claims involving microbiota?

Answer 36

Regular consumptionof at least 3g per day of B-glucan fibre found in oats/barley can reduce the risk of heart disease

Question 37

What are claims recomended by WHO involving gut microbiota?

Answer 37

Increased consumption of dietary fibre can reduce the risk of colon cancer Consumption of prebiotics improves calcium uptake

Question 38

What are consequences to the microbiota when exposed to antibiotics?

Answer 38

Kill commensals as well as pathogens Leads to low diversity Can cause spread of antibiotic resistant bacteria

Question 39

In terms of the microbiota, what happens during and immediately post-antibiotic treatment?

Answer 39

Decreased microbial diversity Opportunity for pathogen colonisation C. Difficile expands to occupy empty niches, causing overgrowth that produces toxins

Question 40

What does CDAD stand for?

Answer 40

C. Difficile Associated Diarrhoea

Question 41

What does an overgrowth of C. Difficile cause?

Answer 41

CDAD

Question 42

What are the main symptoms of CDAD?

Answer 42

Diarrhoea Abdominal pain Fever

Question 43

Do antibiotics have an effect on C. Difficile spores?

Answer 43

No, they are resistent

Question 44

What can be said about strains of C. Difficile and antibiotics?

Answer 44

Some strains are antibiotic resistent

Question 45

What is the initial treatment for CDAD?

Answer 45

Antibiotic therapy (cures about 75% of patient)

Question 46

What is the best treatment for CDAD when antibiotics do not work?

Answer 46

Faecal microbial transplantation (FMT)

Question 47

What can failure ot faecal microbial transplantation (FMT) to treat CDAD lead to?

Answer 47

Death

Question 48

How does FMT work?

Answer 48

Question 49

What does the success rate of FMT depend on?

Answer 49

Clinic experience Application method Pre-treatment No subsequent antibiotic threatment

Question 50

What infections do faecal transplants only work on?

Answer 50

C. Difficile

Question 51

What is the criteria for bacteria to be used for a faecal transplant?

Answer 51

Sensitive to antimicrobials Easy to culture Representative of gut commensal bacteria Added in relative abundances representative of composition of healthy gut