Lecture 4. The Microbiome Flashcards
What are all humans covered in?
Bacteria
What are the six main bacteria that cover the body?
Firmicutes (Gram +ve)
Bacteroidetes (Gram -ve)
Fusobacteria (Gram -ve)
Actinobacteria (Gram +ve)
Cyanobacteria
Proteobacteria (Gram -ve)
What did Elie Metchnikoff hypothesise?
Seeding the gut with healthy bacteria by drinking fermented milk products could fight off harmful bacteria and prolong life, modifying the gut microbiome to replace bad bacteria with good bacteria
How many bacteria do healthy individuals contain?
Trillions
What factors affect the gut microbiome?
Section of the GIT
Age
Diet
How many reference strains have the Human Microbiome Project isolated and sequenced?
1,300
What is the microbiome influenced by?
Mode of delivery
Mode of initial feeding
Ageing process
Diet
Geography
Medication
Stress
How does delivery mode influence microbiome composition?
Vaginal birth: infant inoculated with vaginal microbiota; larger population of Bacteroidetes than Firmicutes compared to caesarean section
Caesarean section: infant inoculated with skin microbiota
Do aerobic or anaerobic organisms colonise the microbiome first?
Aerobic
What can change the gut community over the first year of life?
Weaning, breastfeeding, different types of food and antibiotic use
How many bacteria does breast milk contain?
Over 600 different species including beneficial Bifidobacterium spp. and oligosaccharides that stimulate the growth of the Bifidobacterium spp.
What do breast-fed infants have a lower concentration of?
Some pathogens such as Clostridia spp.
What bacteria is more common in the microbiome of the elderly?
Firmicutes
What bacteria is more common in the microbiome of the young?
Actinobacteria & Proteobacteria
What is caused by old age?
Dysbiosis due to change in diet
