Lecture 14: Human Microbiome

Question 1

what line of defense is the human microbiome?

Answer 1

first-line defense

Question 2

what is covered by the human microbiome?

Answer 2

skin and mucous membranes are covered with the human microbiome

Question 3

what is the human microbiome also called?

Answer 3

normal microbiota or normal flora

Question 4

what is the human microbiome?

Answer 4

a group of microorganisms that colonize body surfaces

Question 5

what does the human microbiome include?

Answer 5

bacteria, archaea, protozoa, fungi, and viruses

Question 6

does each person have a unique microbiome signature? how about twins?

Answer 6

yes each person does

Question 7

how is the human microbiome harmful?

Answer 7

-It is harmful if there is an imbalance (dysbiosis) and overgrowth (superinfection)
-Incorrect location (if E. coli is in the urinary tract and not the colon)

Question 8

how is the human microbiome beneficial?

Answer 8

it is beneficial under normal circumstances

Question 9

what is the main function for us of the human microbiome? (regarding protection)

Answer 9

It protects us from harmful organisms.
-It covers binding sites (so there is no space for foreign invaders).
-Compete for nutrients (so there is no food for foreign invaders).
-Makes antimicrobial chemicals
-It alters pH, O2, and other parameters

Question 10

what can happen in you take a broad-spectrum antibiotic?

Answer 10

You have to take probiotics to replace the normal microbiota because the antibiotic kills all the bacteria.

Question 11

what do we do for the human microbiome?

Answer 11

we provide food and shelter for it to grow

Question 12

what type of relationship do we have with the human microbiome?

Answer 12

mutualistic relationship

Question 13

what is the main function for us of the human microbiome? (regarding oral tolerance)

Answer 13

It helps develop oral tolerance - hygiene hypothesis.
-In young children, the immune system needs to be educated to differentiate between harmless and harmful microbes.
-Accomplished by exposure to various harmless microbes in the environment; mud, plants, animals, people - that become a part of their microbiome.

Question 14

in the hygiene hypothesis, what happens if the environment is too clean when a kid is developing?

Answer 14

If the environment is “too clean”, then the immune system fails to undergo training and launches attacks against harmless microbes, causing a higher incidence of allergies and autoimmune disorders.

Question 15

where is the human microbiome found?

Answer 15

Mostly surfaces.
-Skin and mucous membranes, especially the beginning and end of tubes. (Most common in the large intestine).
-Recently found in lungs, brain, and bladder.

Question 16

why were scientists surprised when they found human microbiome is the lungs, brain, and bladder?

Answer 16

because we used to think they were sterile, but no organs are really sterile

Question 17

what are two ways be get our normal microbiota?

Answer 17

-Vaginal microbes: fetuses get their microbiome through vaginal delivery. It is lacking during C-section.
-Breastmilk

Question 18

how do we get our normal microbiota from breastmilk?

Answer 18

-Getting microbes, including gut microbes.
-Getting prebiotics, which are sugars that exclusively feel the gut bacteria for more microbes to grow.

Question 19

what is the most important time to develop a normal microbiome?

Answer 19

During the first 3 years of life - it goes up and down but is generally pretty stable

Question 20

what has a healthy and diverse microbiome been shown to do?

Answer 20

a healthy and diverse microbiome
has been shown to be key to
good health

Question 21

what is resident microbiota/flora?

Answer 21

stable and long term

Question 22

what is transient flora?

Answer 22

dynamic and short term

Question 23

what can the composition of the microflora change depending on?

Answer 23

diet, lifestyle, antibiotics, etc.

Question 24

differences in microbiomes can be correlated with what illnesses?

Answer 24

ranging from IBD to cancer to depression

Question 25

how can you treat a diseased microbiome with “good” microbes? aka what is an example?

Answer 25

fecal transplants for Clostridiodes difficile

Question 26

what is the prevention like for a diseased microbiome?

Answer 26

you can maintain a healthy microbiome by eating right, exercising, and being in nature

Question 27

which of the following is not true about normal microbiota?
1. They are part of the second-line defenses.
2. They can be harmful in the wrong location.
3. They are killed by broad-spectrum antibiotics.
4. They influence our state of health and disease.

Answer 27

1. They are part of the second-line defenses.

Question 28

How can normal microbiota protect us from pathogens?
1. They cover binding sites
2. They alter local conditions
3. They compete for nutrients
4. They make antimicrobial chemicals
5. All of the above

Answer 28

5. All of the above

Question 29

Which of the following is not a possible side-effect when given a broad-spectrum antibiotic?
1. Superinfection with Clostridium difficile
2. Dysbiosis of the human microbiome
3. Development of oral tolerance
4. Vaginal yeast infections
5. Decrease in first line defenses

Answer 29

3. Development of oral tolerance

Question 30

What is the most common site for normal microbiota in the body?
1. Skin
2. Throat
3. Mouth
4. Large intestine
5. Nose

Answer 30

4. Large intestine

Question 31

The human microbiome is beginning to be explored in people to determine possible “healthy” and “disease-causing” profiles. One goal of this process is to someday provide normal microbiota therapy through replacement, addition or modification. Discuss fecal transplant as a successful replacement therapy for victims of recurrent C diff infections.

Answer 31

Answer: In patients with recurrent C diff infections, fecal transplant has proven to be an effective treatment. The patient is given a solution of fecal material from a donor (usually a spouse or relative) via colonoscopy. The fecal bacteria colonize the patient and block C diff attachment. There is obviously a “yuck” factor to this process, so new developments include pills with concentrated amounts of fecal bacteria.

Question 32

The microorganisms that are OCCASIONALLY found in or on the body are called

Answer 32

transient microbiota

Question 33

Newborn babies acquire microbiota through…

Answer 33

contact with the mother’s skin, through the vaginal canal during birth, breastfeeding, and from the environment.

Question 34

The “hygiene hypothesis” proposes that…

Answer 34

lack of exposure to microbes can lead to development of allergies.

Question 35

T/F: The composition of your microbiome is dynamic and changes over your lifetime.

Answer 35

True

Question 36

Human microbiome comprises of the following microbes:
1. viruses
2. bacteria
3. archaea
4. protozoa
5. fungi
6. all of the above

Answer 36

6. all of the above

Question 37

is the human microbiome part of the innate or adaptive immune system?

Answer 37

the innate immune system, since it is a first-line of defense and covers skin and mucous membranes.

Question 38

what are probiotics?

Answer 38

Probiotics are supplements that replace the normal microbial flora if it is lessened due to antibiotics