L4: Human Microbiome II Flashcards

1
Q

factors influencing the gut microbiome - in utero

A
  • antibiotic use by the mother
  • mother’s diet
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2
Q

factors influencing the gut microbiome - parturition

A
  • hospital setting
  • length of gestation
  • mode of delivery (c-section vs vaginal)
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3
Q

factors influencing the gut microbiome - infancy

A
  • environment
  • prebiotics/probiotics
  • formula feeding vs breastmilk
  • introduction of solid food
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4
Q

explain the evolving microbiome from pregnancy to early infancy - childhood

A
  • diverse
  • no dominant species
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5
Q

explain the evolving microbiome from pregnancy to early infancy - reproductive age

A
  • microbiome composition changes
  • Lactobacillus is selected for
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6
Q

explain the evolving microbiome from pregnancy to early infancy - menopause

A
  • diversity goes down
  • Ureaplasma is selected for
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7
Q

how does the vaginal microbiome change?

A
  • it changes with the menstrual cycle
  • bacterial abundance peaks during ovulation bc of estrogen levels rising
  • which microbe increases is different for each individual
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8
Q

what species dominates the vaginal microbiome in women of reproductive age?

A

Lactobacillus because it keeps pH low

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9
Q

vaginal microbiome in women of reproductive age - what about women who do not have a domination of Lactobacillus spp.

A
  • they instead have a much more diverse microbiome
  • they instead have more anaerobic bacteria
  • a case for many women of color
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10
Q

vaginal microbiome in women of reproductive age: more anaerobic bacteria - how is the pH kept low

A

the anaerobic bacteria can produce lactic acid that will keep the pH low

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11
Q

what is a nugent score

A

a way of evaluating vaginal microbiota for bacterial vaginosis

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12
Q

what is bacterial vaginosis (BV)

A
  • characterized by a shift in the composition of the normal vaginal microbiome
  • microbiome changes from Lactobacillus species to a mixture of anaerobic and facultative anaerobic bacteria
  • known as the microbiome of disease
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13
Q

why is BV dangerous

A
  • it is not effective at keeping pH low
  • causes a high risk of pre-term birth
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14
Q

BV vs normal microbiome - what does a Lactobacillus-dominated microbiome produce

A
  • lactic acid
  • bacteriocins
  • hydrogen peroxide
  • all keep the pH low
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15
Q

BV vs normal microbiome - what does a BV microbiome produce

A
  • SCFAs and pH will be increased
  • pro-inflammation
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16
Q

BV vs normal microbiome - is BV truly a microbiome of disease

A
  • no
  • some people naturally have more anaerobic bacteria and they may not show symptoms of BV
  • they are just more likely to have colonialism of opportunistic bacteria
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17
Q

how is the human vaginal microbiome unique

A

humans have 70% Lactobacillus spp. while other mammals only have 1%

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18
Q

how is the human vaginal microbiome unique - what is the proposed reason for this

A

vaginal pH of humans evolved to be low to make associations with Lactobacillus spp. since they resided in the gut

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19
Q

the microbiome in early life - birth

A
  • vaginal delivery: Lactobacillus was received from the mom
  • c-section: Staphylococcus, Propionibacterium. Not from mom but from the environment
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20
Q

the microbiome in early life - infant

A
  • milk consumption: Bifidobacterium, Lactobacillus
  • solid food introduction: Bacteroides, Clostridiales
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21
Q

the microbiome in early life - toddler

A
  • full adult diet
  • can still find early microbiome association prevalent
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22
Q

what is the impact of delivery mode on the infant

A

c-section babies are more prone to develop allergies, chronic inflammatory diseases, and metabolic disease

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23
Q

impact of delivery mode on the infant microbiome - c-section

A
  • horizontal gene transfer
  • specifically Staphylococcus and Propionibacterium
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24
Q

what is the impact of delivery mode on the infant - vaginal

A
  • vertical transmission
  • Lactobacillus
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25
Q

how may RSV be prevented in infants

A
  • breastfeeding
  • human milk oligosaccharides (hMOSs) reduces the viral load and inflammatory signaling
  • it travels to the blood and lungs
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26
Q

what is respiratory synoptical virus (RSV)

A

leading cause of lower respiratory infections which is a major source of infant mortality

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27
Q

factors influencing microbiome composition - baby

A
  • formula-fed: Firmicutes is dominant
  • breastfed: Actinobacteria is dominant
  • solid-food: Bacteroidetes
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28
Q

factors influencing microbiome composition - toddler

A
  • healthy: Bacteroidetes
  • antibiotic treatment: too much Bacteroidetes and too little Firmicutes
  • malnutrition: Proteobacteria
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29
Q

factors influencing microbiome composition - adult - elderly

A

Firmicutes

30
Q

how does the gut microbiome change in mother and child

A
  • early microbiome: child resembles mother
  • gets less similar as child gets older
31
Q

how does the oral microbiome change in mother and child

A

changes between mother and child are visible after 6 months

32
Q

what are the habitat for the oral microbiome

A
  • supragingival plaque (teeth and gums)
  • buccal mucosa (inner cheek)
  • tongue dorsum (upper surface of the tongue)
33
Q

oral microbiome - what is the most common microbe

A
  • biofilms in teeth and gums
  • buccal mucose: Strptococcus spp. is dominant
  • tongue: more diverse sets of microbes
34
Q

explain the microbial colonization of freshly cleaned teeth

A
  1. Streptococcus and Actinomyces
  2. Streptococcus and Actinomyces attract more proteins
  3. Veillonella
  4. Porphyromonas
  5. Fusobacterium
  6. Treponema and yeast Candida
35
Q

microbial colonization of freshly cleaned teeth - Streptococcus and Actinomyces

A
  • they are early colonizers
  • attracted to statherin in saliva
  • will colonize again after brushing your teeth
36
Q

microbial colonization of freshly cleaned teeth - Streptococcus and Actinomyces attract more proteins

A
  • amylase, lactoferrin, and other proteins
  • to assist with colonization
  • these then form thick biofilms
37
Q

microbial colonization of freshly cleaned teeth - Veillonella

A
  • Veillonella and other bacteria colonize the teeth
  • Veillonella is attracted to Actinomyces
38
Q

microbial colonization of freshly cleaned teeth - Porphyromonas

A
  • anaerobic bacteria Porphyromonas colonize the teeth
  • its attracted to the anaerobic conditions
  • biofilm becomes thicker and makes it hard to get rid of
39
Q

microbial colonization of freshly cleaned teeth - Fusobacterium

A

anaerobic microenviornemtns allow the interaction of Porphyromonas with Veillonella followed by the adherence of another anaerobe Fusobacterium

40
Q

microbial colonization of freshly cleaned teeth - Treponema and yeast Candida

A

colonization by Treponema and yeast Candida

41
Q

plaque growth rate and inflammation response - unbrushed teeth

A

plaque had some growth rate but different inflammation rate

42
Q

plaque growth rate and inflammation response: brushed teeth - cytokines vs other bacteria

A
  • cytokines: low inflammation expressed
  • other bacteria: started a inflammation response as soon as the biofilm began to form
43
Q

plaque growth rate and inflammation response - brushed teeth

A

bacteria accumulation is steady overtime

44
Q

plaque growth rate and inflammation response - is it the same for every individual?

A
  • no
  • people with the same microbiome will have different responses and rates
45
Q

what are dental caries

A
  • dense biofilm formation in a specific part of the teeth
  • categorized by the abundance of:
    1. biofilm-forming bacteria
    2. acid-producing and acid-tolerant bacteria
46
Q

dental caries - what embodies all 3?

A

Streptococcus mutants

47
Q

what is periodontal disease

A
  • an inflammatory disruption in the host-microbial homeostasis of the periodontal pocket
  • results in biofilm colonizing inside the gums and the bacteria will start to secrete molecules that degrade teeth
  • categorized by microbial dybiosis
48
Q

periodontal disease - microbial dybiosis

A
  • a decrease in the abundance of Proteobacteria and Acinobacteria
  • increase in the abundance of Bacteroidetes and Firmicutes
49
Q

periodontal disease - what bacteria are constantly enriched

A
  • Porphyromonas gingivalis
  • Fusobacterium nucleatum
50
Q

periodontal disease and various pathologies

A
  • positive correlation
  • lesions in gums can cause bacteria to travel to the gut and through the blood stream
  • this can then cause an inflammatory response where molecules produced by bacteria travel and activate inflammation in the gut
51
Q

periodontal disease and variaous pathologies - example

A
  • Alzheimer’s disease
  • correlated with gum disease
52
Q

skin microbiome - explain the skin

A
  • human body’s largest organ
  • serves as a physical barrier
  • heavily colonized by diverse microorganisms that sit on the surface of the skin (epidermis) but also reside deep in hair and glands
53
Q

skin microbiome - what factors influence skin microbiome diversity

A
  • host physiology
  • environment
  • immune system
  • host genotype
  • lifestyle
  • pathobiology
54
Q

skin microbiome: what factors influence skin microbiome diversity - host physiology

A
  • sex
  • age
  • site on skin
55
Q

skin microbiome: what factors influence skin microbiome diversity - environment

A
  • climate
  • geographical location
56
Q

skin microbiome: what factors influence skin microbiome diversity - immune system

A
  • previous exposures
  • inflammation
57
Q

skin microbiome: what factors influence skin microbiome diversity - host genotype

A
  • susceptibility genes
  • such as filaggin
58
Q

what factors influence skin microbiome diversity: host genotype - what is filaggin

A
  • a protein in the epidermis
  • it is related to how much keratin is deposited in the skin
  • this relates to how thick the epidermis is
59
Q

skin microbiome: what factors influence skin microbiome diversity - lifestyle

A
  • occupation
  • hygiene
60
Q

skin microbiome: what factors influence skin microbiome diversity - pathobiology

A
  • underlying conditions
  • such as diabetes
61
Q

skin microbiome vs other areas

A
  • skin: more diverse and more spread out in a phylogenetic tree
  • other areas: less diverse and more close to each other in a phylogenetic tree
62
Q

skin microbiome - what species is dominant in sebaceous areas

A

Propionibacterium spp.

63
Q

skin microbiome - what species is dominant in moist areas

A

Staphylococcus and Corynebacterium spp.

64
Q

skin microbiome - what species is dominant in dry areas

A
  • a mixed representation from phylum Actinobacteria, Proteobacteria, Firmicutes, and Bacteroidetes
65
Q

skin disorders associated with the microbiome

A
  • acne
  • atopic dermatitis (AD)
  • rosacea
66
Q

skin disorders - acne

A

involves androgen-induced increases in:
- sebum production
- altered keratinization
- inflammation
- dysbiosis of facial skin

67
Q

skin disorders: acne - what are the 2 major microbes associated with acne

A
  • Staphylococcus epidermidis and Cutibacterium acnes
  • contribute to acne by penetrating follicles and creates an inflammatory response
  • but is also known to promote health
68
Q

skin disorders: acne - how do Staphylococcus epidermidis and Cutibacterium acnes promote health

A

by inhibiting growth and invasion of pathogens

69
Q

skin disorders - atopic dermatitis (AD)

A
  • dysfunction of the skin barrier caused by mutation in the gene that encodes for filaggrin
  • a protein involved in cornification
70
Q

skin disorders: AD - what microbes are dominant

A
  • increased bacterial colonization of Staphylococcus aurenus and viral infections
71
Q

skin disorders: AD - that are the 2 stages

A
  • non-flare: microbiome if still different but has less Staphylococcus aurenus
  • flare: noticeable increase in Staphylococcus aurenus colonization
72
Q

skin disorders - rosacea

A
  • disregulstion of the immune system
  • imbalance of in microbial composition
  • but Demodex mite has been found on healthy skin is significantly increased which activates the inflammation response