Gut Microbiota Flashcards
what is the composition of the normal gut flora?
Most animals are germ free in the uterus
When born, most are colonised with dozens of species of bacteria which remain with the organism until death. (microbiota)
When are the normal flora normal?
Only normal when appropriately situated in the gut and not the bloodstream
Why is the gut microbiota required?
to maintain the gut health of the organism
What are transient microbiota?
Microbials that inhabit the organism for a brief period of time:
some cause disease
most do not
what is symbiosis?
benefit from both partners.
What is commensalism?
Shelter and food benefit
What is mutualism?
Reciprocal benefit
What is parasitism?
unilateral benefit
what mechanisms do normal flora compete by?
Protection:
Layer formation by normal flora
Waste production formation by normal flora
immune stimulation
Disease: Large inoculum antimicrobial drugs host factors (reduced peristalsis) physical destruction (irradiation)
What area of the human body contains the most bacteria colonies?
Intestines (1000g)
why are the normal flora located in particular locales?
most commensal bacteria specifically adapted to life in one particular niche
Most bacterial uses specific ligands for attachment to specific receptors located at colonisation sites in particular tissues.
What are some normal commensal bacteria located in the mouth?
Alpha - streptococci
Diphtheroid’s
spirochetes
What are some normal commensal bacteria located in the stomach?
Sparse bacteria
Lactobacili
Fusobacterium
What are some normal commensal bacteria located in the Small bowel?
Sparse flora
Increasing in numbers with distance from the stomach
What are some normal commensal bacteria located in the colon?
Lots of bacteria - anaerobes
Coliforms
streptococci
