Microbiome/Dysbiosis

Question 1

Microbiome vs Microbiota vs Dysbiosis

Answer 1

Microbiome: Microbiota + their habitat

Microbiota: microorganisms found on skin or mucous membranes of healthy people

Dysbiosis: altered microbiome

Question 2

Intestinal Microbiota

- list common microorganisms in large intestine (5)

Answer 2

• enterococci spp.
• Enterobacteriaceae (e. coli, klebsiella spp.)
• Bacterioides spp.
• Clostridium spp.
• Candida spp.

Question 3

Intestinal Microbiota by Phyla!

• list phyla in order of most to least in intestine (5)
• -> also list what species are in each
• what are the 2 ways we determine this?

Answer 3

Phyla:

1) Firmicutes (Enterococcus spp., Clostridium spp.)
2) Bacterioidetes (Bacterioides spp.)
3) Actinobacteria
4) Proteobacteria (enterobacteriaceae, E. coli)
5) Others

1) 16S rRNA gene phylotyping
2) Metagenomic whole genomic sequencing

Question 4

List all conditions that have a proposed link to the altered intestinal microbiome (7)

Answer 4

• C. diff infection
• Obesity
• Diabetes
• Depression
• IBD
• CAD
• Asthma

Question 5

C. difficile and dysbiosis

• explain exposure to C. diff and outcomes as related to c. diff
• in patients with recurrent CDI, what are the changes in intestinal phyla? (2)
• treatment for recurrent CDI?
• -> and results of this treatment (2)

Answer 5

C. diff exposure and outcomes:
1) If exposed to C. diff with healthy microbiome: asymptomatic C. diff colonization

2) If exposed to C. diff with dysbiosis: C. diff infection
3) C. diff infection: 25% recurrent disease; 75% no recurrent disease

Intestinal phyla changes:

• increased proteobacteria
• decreased diversity

Treatment:
- fecal microbiota transplantation (FMT)

Results:

• decreased proteobacteria
• increased diversity

Question 6

C. diff and obesity

• changes in intestinal microbiota in obese patients? (1)
• change in diet (what dietary changes, what do they do)
• mouse twin experiment

Answer 6

Changes:

• increased ratio of firmicutes:bacterioidetes
• change in diet (decreased fat and decreased carbohydrates) results in decreased firmicutes to bacterioidetes, to look more like lean microbiota
• mouse twin study: twins (one lean one obese) microbiota introduced to mice. One mouse remained lean (the one with lean microbiota) one gained adiposity (the one with obese microbiota).

Question 7

Things throughout life that impact microbiota

• baby
• toddler
• adult

Answer 7

Baby:
- milk, formula, solid food

Toddler:
- antimicrobials, malnutrition

Adult:
- obesity

Question 8

Causes of dysbiosis

- list (3)

Answer 8

Dysbiosis:

1) Antimicrobials
2) Inflammation
- Infectious colitis
- Chemotherapy induced mucositis
- post-operative inflammation
3) PPIs (decreased gastric acid production)

Question 9

Impact of dysbiosis at different life stages

• age 0-1
• age 1-5
• adults

Answer 9

Ages:
0-1
- antimicrobials = higher risk of childhood obesity, allergies, asthma, type 1 diabetes

1-5
- repeated use of antimicrobials = risk of type 2 diabetes

adults:
- risk for C. diff

Question 10

Dysbiosis Interventions

• list (3)
• which one has definitive data??

Answer 10

1) Fecal Microbiota Transplantation
2) Dietary changes (reduce fat and carbohydrates)
3) Probiotics

ONLY FMT is research-backed!!!