Lecture 8- Human-Microbe interactions

    Cards (41)

    • How many bacteria are estimated to be in the microbiota?
      3.8 x 1013^{13} bacteria
    • What are commensals in the context of microbiota?
      They form permanent interactions with us
    • Where are bacteria found in the human body?
      On all surfaces of the body
    • What does the body provide for bacteria?
      Nutrients, growth factors, temperature, pH
    • What is the microbiota?
      Collection of microorganisms living in and on us
    • What was the microbiota previously called?
      'Normal' flora
    • What percentage of stool dry matter is microbial mass?
      60%
    • How does the genetic information from microbes compare to the human genome?
      More genetic information from microbes
    • What is the biodiversity like in the skin microbiota?
      Restricted biodiversity
    • What type of bacteria are found in sweat glands and on skin?
      Resident and transient bacteria
    • Name a resident bacterium found on the skin.
      MRSA
    • Name a transient bacterium found on the skin.
      E.coli
    • What is the biodiversity like in the nasal cavity microbiota?
      Restricted biodiversity
    • What are opportunistic pathogens found in the nasal cavity?
      Neisseria meningitidis, Haemophilus influenzae
    • What is the biodiversity like in the oral cavity microbiota?
      High biodiversity
    • How many bacterial species are found in dental plaque?
      Over 300 species
    • What is the role of primary colonisers on teeth?
      They form micro-colonies on tooth surfaces
    • What is the pH of the stomach?
      pH 2
    • What is the significance of Helicobacter pylori in the stomach?
      It colonises the stomach in 50% of people
    • What can Helicobacter pylori lead to?
      Gastritis and gastric cancer
    • What is the pH of the small intestine?
      pH 4-5
    • What is the bacterial biomass like in the colon?
      Huge bacterial biomass
    • How many cells per gram of contents are found in the colon?
      10101011^{10}-10^{11} cells
    • What type of bacteria are the majority in the colon?
      Obligate anaerobes
    • How many different species of bacteria are in the GI tract?
      Over 1,000 different species
    • What does gut microbiota provide in terms of calories?
      10% of the calories from food
    • What do gut microbiota convert complex carbohydrates into?
      Short chain fatty acids
    • What happens to germ-free mice when colonised with cecal microbiota?
      They gain 60% more body fat
    • What is dysbiosis?
      Imbalance of normal flora
    • What can oral antibiotics do to normal flora?
      Inhibit the normal flora
    • What can happen if a wide spectrum antibiotic is used?
      Virtual sterilisation of the intestinal tract
    • What can invade after dysbiosis occurs?
      Opportunistic pathogens
    • What is the gut-brain axis?
      Connection between gut microbiota and brain function
    • How does tryptamine affect serotonin production?
      It upregulates serotonin production
    • What can increased 4-ethylphenylsulphate lead to?
      Increased stress and anxiety
    • What is faecal microbiota transplant used for?
      Treating multi-resistant Clostridium difficile infection
    • What are the roles of gut microbiota?
      • Crucial for health
      • Digestion of food
      • Produces beneficial metabolites
      • Strengthens immune system
      • Protects surfaces from pathogens
      • Imbalance results in disease
      • Influences gut-brain axis
    • What are the effects of dysbiosis on health?
      • Inhibits normal flora
      • Allows opportunistic pathogens to invade
      • Can lead to ulcers and infections
      • Affects mood and behavior through gut-brain axis
    • How does gut microbiota influence calorie harvesting?
      • Provides 10% of calories from food
      • Converts complex carbohydrates to short chain fatty acids
      • Affects body fat and insulin resistance
    • What is the impact of birth method on gut microbiota?
      • Acquired during passage through birth canal
      • Caesarean birth reduces colonisation by specific bacteria
      • Exclusive breastfeeding selects for beneficial bacteria