Microbiome Flashcards
Where are microbes typically found?
On body surfaces (outer and inner)
Internal regions are typically ___?
Sterile
Where do we all begin life?
In a sterile womb environment
How does the colonization of bacteria occur?
In the birth canal
From mom’s skin
Breast milk
When does colonization begin?
At birth
What is in breast milk?
600 species of bacteria
Prebiotics which contain growth factors and food for bacteria
What is found in the birth canal?
Skin bacteria that only colonizes during the 3rd semester of pregnancy
What causes differences in gut microbiomes in babies?
Diet and delivery
What do formula-fed babies have an increased frequency of?
Firmicutes
What are the differences in microbiomes in Western countries?
Fewer E. coli
More lactococcus and lactobacillus
What is competitive exclusion?
Normal flora produce inhibitor compounds to decrease pathogen growth
Why is a healthy microbiome full?
There is no vacancy
Disruption of microbial barriers increase the chance of invasion by pathogens
What do breast fed babies have?
Fewer bad bacteria even after weaning
What is ETBF excluded by?
NTBF = commensal bacteria in the gut
What is ETBF associated with?
Colitis
How does NTBF kill ETBF?
Produces a perforin-like protein by T6SS which is a TLR2 agonist and will also enhance the target immune response
What 3 toxins does C. diff produce?
TcdA, TcdB = glucosyl-transferases which inactive G-protein signals
CDT = binary toxin that acts as ADP-ribosomal transferase
What does TcdA/B do?
Disrupts epithelial attachment
What does binary toxin do?
Modifies actin cytoskeleton to facilitate bacterial adhesion
What is the treatment for C. diff?
Fecal transplant = 85% cure rate
How are gut genes turned on?
by bacterial growth factors
What vitamins does bacteria produce?
Vit K = E. coli
90% of serotonin is bacterially produced
How do bacteria aid in digestion?
Vast majority of digestive enzymes needed are bacterially produced
Helps digest fibers and lactose
How do bacteria modulate the immune system?
Trains the immune system to distinguish between flora and pathogens
