Human Microbiota

Question 1

Define microbiota

Answer 1

Bacteria living in and on the body

Question 2

Where does bacteria reside?

Answer 2

Everywhere, some sterile sites (brain, lungs, blood)

Question 3

Ratio of bacterial cells to human cells?

Answer 3

1.3 : 1

Question 4

Functions of bacteria? (4)

Answer 4

1) Prime immune system
2) Metabolise carbs and protein
3) Induction of angiogenesis
4) Colonisation resistance

Question 5

Sterile womb theory?

Answer 5

Microbiota acquired through vaginal delivery or microbes in the environment if C-section

Question 6

In utero colonisation?

Evidence?

Answer 6

Bacteria acquired from colonies in placenta and amniotic fluid - weak evidence due to inappropriate controls, insufficient detection and no evidence of bacterial viability

Question 7

What is responsible for microbiota development? (3)

Answer 7

1) Environment
2) Diet
3) Antibiotic use

Question 8

At what age has a bacterial community settled?

Answer 8

3 years

Question 9

What are the main classes of bacteria in the gut? (2)

Answer 9

1) Fimicutes

2) Bacteriodetes

Question 10

What are the metabolic products of dietary components? Properties?

What happens if there is excess?

Answer 10

Gas and short-chain fatty acids (acetate, butyrate, propionate) - Anti-inflammatory, anti carcinogenic

Excess protein forms aromatic amino acids, broken to ammonia and phenols (carcinogenic)

Question 11

Relationship between gut microbiota and obesity?

Evidence?

Answer 11

Reduced diversity of population - less Bacteriodetes

Mouse model - Obese mouse colonised by lean mouse (eating faeces), starts to lose weight

Question 12

Define dysbiosis

Answer 12

Imbalance in normal composition of gut microbiota

Question 13

Give two examples of conditions arising from dysbiosis of the colon

Answer 13

C. difficile

Candida infections

Question 14

Risk factors for C.diff? (2)

Answer 14

1) Over 65

2) Prolonged antibiotic use (broad spec)

Question 15

How does C. diff arise?

Answer 15

Absence of competition allows spores to germinate and produce toxins which break down tight junctions, epithelia less resistant to liquid flow

Question 16

Treatment for mild C. diff?

Answer 16

PO Metronidazole 400mg 10-14/7 TDS

Question 17

Treatment for moderate C. diff?

Answer 17

PO Metronidazole 400-500mg 10-14/7 TDS

Question 18

Treatment for severe C. diff?

Answer 18

PO Vancomycin 125mg QDS 10-14/7

PO Fidaxomycin 200mg BD 10/7

Question 19

Novel treatment idea for C. diff?

Answer 19

Introduction of microbiota - isolate from faeces

Question 20

SIGHT Infection Control? Purpose?

Answer 20

Suspect
Isolation
Gloves and aprons
Hand washing (soap and alcohol gel)
Test stoll for toxins

Reduce rates of C. diff