The human microbiome part 2 Flashcards
(18 cards)
What is microbiota
describes the living microorganisms found in a defined environment, such as oral and gut microbiota.
what is microbiome
the collection of genomes from all the microorganisms in the environment, which includes not only the community of the microorganisms, but also the microbial structural elements, metabolites, and the environmental conditions
microbiome is a what type of balance
Dynamic balance
Is a normal microbiome easy or hard to define and how do we know what is normal?
it’s hard to define since everyone’s is different
studies don’t also show the same normal
what is dysbiosis
This defines Imbalance in the microbiota which either:
This can be the Causes a disease
Or can be Reflects a disease state
Where can dysbiosis be but its most commonly in the
anywhere in the body
GI tract
Dysbiosis linked to a number of diseases in infants with
asthma
Crohn’s disease
inflammatory bowel disease (IBD)
type 1 diabetes
The intestinal microbiota varies as..
we age
in infants = very little diversity but as we age 3 there’s more diversity
largely established at 12 years old
pregnancy: changes in microbiota but it reverts to it’s original structure after delivery
when does colonisation begin for a baby
during birth
GI tract must be colonized before adequate immune function can develop
Numerous factors affect microbiota
medical history and lifestyle choices
Newborn Microbiota
Shortly after birth the “sterile” infant begins to be colonised (or during the birth) (in beginning comes from the mother at the beginning this is for the baby delivered normally)
First bits of bacteria are from the mother as they pass through the birth canal
Vaginal flora
Help Deoxygenate the gut
First contact is with bacteria from the birth canal and surroundings
flora of the female genital tract, sanitary conditions, obstetric techniques, medical staff, vaginal or Caesarean delivery
Skin to skin contact exposes them to mothers skin and mothers microbial skin population
Type of feeding will affect microbiota
So if its Breast vs bottle
Infant Gut Colonisation - where are the initial colonisers from
Enterobacteria (E.coli) and streptococci
Followed strict anaerobes (Bifidobacteria and Bacteroides)
Facultative anaerobes make intestine anaerobic
Allows colonisation by the strict anaerobes
Stabilised at 4 weeks until weaning takes place
Modes of delivery
Major impact on infant microbiome
Significant differences found up to a year after birth
Unclear how long more minor differences may persist
Impact with caesarean delivery
Decrease in Bacteroides, Lactobacillus and Bifidobacterium
There is an Increase in Clostridium (Clostridioides) difficile and skin bacteria e.g. Staphylococcus, Streptococcus and Propionibacterium (Cutibacterium).
These Differences remain significant up to 1 year after birth.
Some immune/allergic diseases and infections are greater after CS delivery.
inflammatory bowel disease, T1D, coeliac disease, childhood asthma and obesity
what is vaginal seeding and when is it carried out?
Infant inoculated with vaginal fluid
this decreases the risk of infant gut dysbiosis
Infant formula or probiotic drops supplemented with … to reduce risk of infant gut dysbiosis
Lactobacillus reuteri
Breast vs Bottle
Breast milk stimulates healthy gut development
Through presence of prebiotics, immunoglobulins, cytokines, growth factors and microbiologic factors. (this is what BREASTMILK contains)
Important for the growth and development of the immune system.
Breast milk contributes 104–106 bacterial cells per day to the infant (this outnumbers inoculation via skin)
Bacterial genera are Bifidobacterium, Lactobacillus, Staphylococcus and Streptococcus.
Bifidobacterium species dominate (able to metabolise human milk oligosaccharides)
B. breve, B. longum, B. dentium, B. infantis and B. pseudocatenulatum.
