Module 5: Section 2B

Question 1

3 benefits of the human microbe

Answer 1

1. Protection from pathogens
2. Nutrient acquistion
3. Immune system development

Question 2

C. difficile and Normal Microbiome Protection

Answer 2

Healthy gut microbes prevent C. difficile spores from germinating, so most people carrying C. difficile have no symptoms

Question 3

Antibiotics and C. difficile Infection

Answer 3

Long or multiple antibiotic treatments can kill healthy gut microbes, allowing C. difficile spores to germinate and produce toxins that cause serious illness

Question 4

Treatment for C. difficile

Answer 4

• C. difficile infections are treated using fecal transplants from healthy donors
• Called “RePOOPulate”

Question 5

Purpose of Fecal Transplant

Answer 5

Fecal transplants are used when antibiotics fail to clear a C. difficile infection

Question 6

Treatment for C. difficile - Weeks 1-36

Answer 6

• Additional antibiotics were given to the patient to try and control the C. difficile
• At week 30, patient was still testing positive for C. difficile so vancomycin was decreased in preparation for a fecal transplant

Question 7

Treatment for C. difficile - Weeks 36-64

Answer 7

• Patient received a fecal transplant
• Monitored for C. difficile by monitoring stool samples and testing for the bacteria
• Even though the patient took several courses of antibiotics, the patient remained free fro, C. difficult for 26 weeks post-treatment

Question 8

Where do we get vitamin B₁₂ and who produces it?

Answer 8

• Gut microbes provide a significant source of vitamin B₁₂ (cobalamin)
• It is only produced by microorganisms, specifically anaerobes

Question 9

Which microbes make vitamin B₁₂ and what is notable about the genes involved?

Answer 9

• Lactobacilli are major producers of cobalamin
• ~30 genes are involved in de novo B₁₂ synthesis

Question 10

Normal microbiome

Answer 10

• High levels of diversity and numbers of microbes
  -Helps keep the immune system on a low level of alert so microbes are prevented from penetrating through the gut wall and into regions of the body where they could become problematic

Question 11

Perturbed microbiome

Answer 11

• Decrease in level of diversity and number of microbes
• Use of antibiotics or other drugs, dietary changes, or life style issues can result in an altered microbiome
• This state can revert back to normal if the perturbance are removed or progress to a state called dysbiosis

Question 12

Dysbiosis

Answer 12

Long term decrease in diversity, although numbers of microbes may be high

Question 13

What caused dysbiosis

Answer 13

• An imbalance in protective microbes that normally prevent pathogen colonization
• It causes gut inflammation, changes nutrient absorption, can trigger autoimmune diseases, and breaks down the protective barrier that keeps microbes in the gut lumen