8 - Human – microbe interaction

What is a microbiota?

Collection of micro-organism in us with mutualistic relationships

What were microbiotas used to be called?

Normal flora

What type of biodiversity of microbiota were in the skin?

Restricted biodiversity

What type of biodiversity of microbiota were in the nasal cavity?

Restricted biodiversity

What were the most typical type of bacteria found in the nasal cavity?

Opportunistic pathogens

What were the most typical type of bacteria found on the skin?

Resident bacteria

What type of biodiversity of microbiota were in the oral cavity?

High biodiversity

Describe the bacterial colonisation of teeth?

Tooth surface with micro-colonies of primary coloniser / bacteria attach to salivary pellicle receptors on the tooth

What microbiotas are in the GI tract stomach?

Helicobacter pylori / Gram -ve, motile / colonise mucosa of stomach in 50% of ppl

What bacteria do 80% of gastric ulcer patients carry?

H.pylori

How can H.pylori lead to gastric cancer?

H.pylori → gastritis → gastric cancer

What is dysbiosis?

Imbalance in the microbiota

How do oral antibiotics cause dysbiosis?

Oral antibiotics inhibit the normal flora

What happens to intestinal tract if a wide spectrum antibiotic is used?

virtual sterilisation / opportunistic pathogens can invade and cause life threatening diarrhea

What problems can opportunistic pathogen invasion of the intestinal tract cause?

Life threatening diarrhea (ulcers in colon) or candida albican (yeast) causing oral thrush

How are gut microbiota acquired?

Through birth canal

What can reduce colonisation of the gut microbiota (in early development)?

Caesarian birth

What does caesarian birth do to gut microbiota in early development?

Reduce colonisation

What can mark transition to more stable adult gut microbiota?

Introduction to solid foods

What are the 6 roles of gut microbiota?

Digestion / beneficial metabolite production / strengthen immune system / protect surfaces from pathogen / imbalance=disease / gut-brain axis

What is the role of gut microbiota in gut-brain axis?

Regulates brain function / mood and behaviour

What does dysbiosis / gut-brain axis cause an increase production of?

Tryptamine by gut microbiota / 4-ethylphenylsulphate

What does an increase in tryptamine do?

upregulate serotonin production and improve mood

What does an increase in 4-ethylphenylsulphate do?

Absorbed into blood stream and cross into CNS / increase anxiety and stress in rats