Gut Microbiota in Health and Disease Flashcards
What factors affect gut microbiota?
- Disease
- Faecal transplant
- Prebiotics
- Antibiotics
- Probiotics
- Environment
- Diet
- Age
What are many disease caused by?
- Microbes that normally live asymptomatically on the host
- Bacteria colonising a different body site
- General imbalance of microbiota
What are the possible reasons for the decrease in infectious diseases?
- Better disease treatments
- Vaccination
- Health standards
What is the possible reason for the increase in immune diseases?
Westernisation
What is the prevalence of IBS related to?
Western countries not latitude
What does inflammation in IBD likely result from?
A dysregulated host immune response to the gut microbiota
What are the general conclusions which can be made from IBD microbiota studies?
- IBD samples tend to cluster separately when compared to non-IBD controls
- Individuals with IBD have reduced bacterial diversity
- Greatly reduced temporal stability in microbiota composition in IBD patients
What do compositional comparison in IBD microbiota studies often show?
- A reduction in Firmincutes
- Increase in facultative anaerobes such as E.coli
- No recurring and consistent putative aetiological agent discovered
What is meant by the non-uniform manifestation of IBD?
Patients have regions of healthy tissue adjacent to inflamed regions
What features of IBD could affect the microbiota of the gut?
- Antibiotic use
- Inflammation
- Diarrhoea
- Host diet
- Host genotype
What can happen to bacterial diversity as a result of broad spectrum antibiotic use?
Reduced bacterial diversity and increases in enterobacteriaceae can occur
Other than antibiotic use, what can result in reduced bacterial diversity and increases in enterobacteriaceae?
Inflammation
Probiotics
- ADDED LIVE BACTERIA
- Live microorganisms which when administered in adequate amounts confer a health benefit on the host
Prebiotic
- FOOD FOR RESIDENT BACTERIA
- A selectively fermented food that result in specific changes in the composition and/or activity of the GI microbiota thus conferring benefits upon host health
Synbiotics
Mixtures of probiotics and prebiotics that beneficially affect the host by improving the survival and implantation of live microbial dietary supplements in the GIT
What is the general conclusion on the effectiveness of probiotics?
Generally probiotics are beneficial in treatment and prevention of GI diseases
What are the problems with the effectiveness of probiotics?
Not all probiotics act in same way thus cant be compared
What are the 8 mechanisms of action fro probiotics?
- Competition (widespread)
- Bioconversions (diet) (frequent)
- Production of vitamins (rare)
- Direct antagonism (frequent)
- Competitive exclusion (widespread)
- Barrier function (widespread)
- Reduce inflammation (widespread)
- Immune stimulation (frequent)
What are some proven health benefits attributed to prebiotics?
- Improved gut function
- Prebiotics the risk of colon cancer
- Prebiotic supplementation of infant formula increases bifidobacteria
- Increase calcium absorption and bone health
- Can lower glycaemic index
What is the consequence of exposure to antibiotics?
Most antibiotics are broad spectrum, which are active against target pathogen but also kill commensal bacteria
How does recurring C diff infection result from antibiotic treatment?
- Decreased microbial diversity
- Opportunity for pathogen colonisation
- Pathogen dominated community
- C.diff expands to occupy empty niches following antibiotic therapy
- overgrowth of C.diff results in toxin production, abdo pain, fever
- C.diff spores are resistant to antibiotics
- Recurring infection
What is the treatment for C.diff associated diarrhoea?
- Antibiotic treatment
- If that doesn’t work then FMT
What does FMT stand for?
Faecal microbial transplantation
How does FMT work?
- Donor sample screened
- Transplanted
- Microbiota repopulate large intestine displacing C.diff preventing reinfection
