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Probiotics > Intestinal flora > Flashcards

Intestinal flora Flashcards

1
Q

How does WHO define probiotics?

A

Live microorganisms which, when administered in adequate amounts,
confer a health benefit on the host.

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2
Q

What is dysbiosis?

A

Unbalanced microbiota

Microbial imbalance, most commonly in the gastrointestinal tract.

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3
Q

What is dysbiosis associated with?

A

intestinal symptoms: gas, bloating, diarrhea, constipation.
Contributes to the “leaky gut” syndrome – increased permeability and
translocation.
* May predispose to a chronic diseases.

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4
Q

What is the safety criteria for probiotics?

A

Be of human origin (not required but recommended)

Non-pathogenic, non-toxic and non-allergenic in nature
Generally recognized as safe (GRAS)

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5
Q

What are the functional criteria of probiotics?

A

Be resistant to destruction by gastric acid and bile salts

Adhere to intestinal epithelial tissue
Be able to colonize the gastrointestinal tract, even in the short term
Be able to utilize nutrients and substrates in a normal diet
Be capable of exerting a beneficial effect on the host through e.g.:
- Modulation of immune responses
- Production of antimicrobial substances
- Influencing human metabolic activities (i.e. cholesterol
assimilation, lactase activity, vitamin production, etc.)

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6
Q

What are the technological criteria of probiotics?

A

Be resistant to destruction by technical processing (maintain good

viability)
Be subjected to scale-up processes
Be stable during transport and storage

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7
Q

What factors do the beneficial effects of probiotics depend upon?

A

a) Microbial strain
b) Level of consumption
c) Duration and frequency of exposure
d) Physiological condition of the individual

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8
Q

What is the recommended daily consumption of probiotics?

A

10^9 CFU/day (e.g., 100 ml of a probiotic product
containing 10^7 CFU/ml).

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9
Q

Why do you need to take probiotics everyday and not just once?

A

Most probiotics do not permanently adhere to the mucosa but exert their effect as they
metabolize and grow during their passage (colonization).
- a daily consumption to maintain effectiveness.

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10
Q

Is there an effect of probiotics if they are dead?

A

On the immune system but nothing else

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11
Q

Mention some beneficial effects of probiotics

A
  • Promote lactose digestion through production of β- D- galactosidase
    enzymes.
  • Build resistance to enteric pathogens through e.g., competition of nutrients
    and adhesion sites, lowering of pH and production of bacteriocins.
  • Increase bioavailability through improved mucosal condition, fermentation of
    food components and production of bioactive compounds.
  • Modulate the immune system
  • Decrease blood lipids
  • Enhance intestinal barrier function
  • Stimulate epithelial mucin production
  • Produce vitamins (especially Vitamin B and vitamin K)
  • Replenish the intestinal flora after antibiotic treatment
  • Control the transfer of dietary antigens
  • Decreases the production of a variety of toxic or carcinogenic metabolites
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12
Q

What are some common probiotics?

A

(L for Lactobacilli, B for Bifidobacteria)
L. acidophilus
B. bifidum
L. casei
B. breve
L. rhamnosus
B. infantis
L. reuteri
B. longum
L. plantarum
B. lactics
L. fermentum
B. thermophilum
L. johnsonii
B. adolescents
L. helviticus
B. animalis
L. farciminis
L. curvatus Enterococcus faecium
L. brevis
Escherichia coli Nissle 1917
L. gasseri
Lactococcus lactis
L. salivarius Propionibacterium freudenreichii
L. cellobiosus
Bacillus clausii
Bacillus oligonitrophilis
Yeast:
Saccharomyces bulardii
Saccharomyces cerevisiae

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13
Q

How many live bacteria do probiotics need to contain to survive GI tract?

A

Probiotics need to contain live bacteria (at least 10^6–10^7cfu/g), be able to survive
through the GI tract and colonize the intestine.

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14
Q

What is NGP?

A

Next generation probiotics

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15
Q

What is the issue with gram negative bacteria?

A

They have endotoxins

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16
Q

Mention some next generation probiotics

A

Prevotella copri
Akkermansia muciniphila
Bacteroides fragilis
Faecalibacterium prausnitzii
Parabacteroides goldsteinii

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17
Q

What are the predominant phyla in the gut?

A

Bacteroidetes (e.g., Bacteroides), Firmicutes
(e.g., Streptococcus)

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18
Q

What are the predominant phyla in the mouth?

A

Firmicutes (e.g., Streptococcus) > Proteobacteria
(e.g., Haemophilus), Bacteroidetes (e.g., Prevotella)

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19
Q

What are the predominant phyla in the skin?

A

Actinobacteria (e.g., Propionibacterium) >
Firmicutes (e.g., Staphylococcus)

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20
Q

What are the predominant phyla in the vagina?

A

Firmicutes (e.g., Lactobacillus)

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21
Q

Does each individual have a unique fingerprint microbiome?

A

Yes, very stable as an adult

22
Q

What is the microbiota?

A

The microorganisms that live in an established environment.

23
Q

What is the microbiome?

A

All microbes and their genomes in a particular environment.

24
Q

Does the colonisation of babies begin at birth?

A

Scientific evidence has provided indications of bacterial presence in the
placenta, umbilical cord, and amniotic fluid in healthy full-term pregnancies.

25
Q

What effects does vaginal delivery have?

A

The microbiome that develops will be composed of species similar to the mother’s
vaginal flora: Lactobacillus spp. and Prevotella spp.

26
Q

What effects do C-section delivery have?

A

The microbiome that develops will be composed of species similar to the skin flora of the
mother and hospital attendants: Proteobacteria and Firmicutes as main phyla, less often
Bifidobacterium spp. and Bacteroides spp., but more frequently Clostridium spp.

27
Q

What differences are seen between formula fed and breastfed babies?

A

Breast-fed: Exhibits lower diversity, higher levels of bifidobacteria and lactobacilli and
lower levels of potential pathogens.
* Formula-fed: More diverse gut microbiota that is dominated by staphylococci,
Bacteroides spp., clostridia, enterococci, enterobacteria.
- Infants fed formula milk achieve an early divergence toward an adult-like
microbiota composition.

28
Q

What is a lack of microbial species richness and
phylogenetic diversity are associated with?

A

Poor health

29
Q

What is the microbiome of elderly generally characterised by?

A

Reduced diversity
* Levels of commensals reduced (e.g., bacteroides, bifidobacteria and
lactobacilli).
* Level of opportunistic pathogens increased (e.g., enterobacteria,
C. perfringens and C. difficile.

  • The microbiota of elderly people (>65 years old) show greater inter-
    individual variation than adults.
30
Q

What are the major factors in microbiome?

A

-Host genotype
-Type of birth
* Excessive hygiene
* Diet (e.g. macronutrients, fiber, phytochemicals, alcohol)
* Stress
* Medicines (e.g. antibiotics, non-steroidal anti-inflammatory drugs)
* Environmental toxins
* Chronic disease
* Aging
* Surgery
* Geographical location

31
Q

Do vegans and vegetarians have a greater richness in microbiome diversity compared to omnivores? Why?

A

Yes
Because fat rich diet means more bile and bile breaks down bacteria. Acts as a detergent. Easier for “bad” bacteria to survive in bile so gram negative will be in higher amounts because survive better in bile.

32
Q

Do vegans and vegetarians have increased Firmicutes:Bacteroidetes ratio? Which other differences can be seen?

A

Yes, and higher
numbers of Prevotella, higher relative abundance of Clostridium
clostridioforme, Faecalibacterium prausnitzii, and Bacteroides
thetaiotaomicron also detected

33
Q

What is Faecalibacterium prausnitzii good for?

A

Butyric acid
Good for epithelial cells in mucosa
Anti-inflammatory

34
Q

What are the effects of diet on microbiota?

A
  • Differences in bacteria directly consumed through food
  • Differences in substrates consumed
  • Variations in transit time through the gastrointestinal system
  • pH
  • Host secretion influenced by dietary patterns
  • Regulation of gene expression of the host and/or his/her microbiota
35
Q

How does carbohydrates affect microbiota?

A

Carbohydrates: Non-digestible carbohydrates, such as resistance starch, and some sugars,
reach colon where they can be fermented by the microbiota.

However, both digestible and non-digestible carbohydrates may influence the
microbiota:
- Digestible carbohydrates from fruits (e.g., glucose, sucrose, and fructose)
reduce Bacteroides and Clostridia.
- non-digestible carbohydrates increase lactic acid bacteria, Ruminococcus spp., Eubacterium
rectale, and Roseburia spp., and reduce Clostridium and Enterococcus spp.
- Both digestible and non-digestible carbohydrates increase bifidobacteria.

36
Q

How does proteins affect microbiota?

A

Proteins: Protein consumption correlates positively with microbial diversity but animal
and plant-proteins influence the gut microbiota in different ways:
- Individuals consuming a high animal protein diet, from meat which is also high in fat,
have lower abundances of e.g., Roseburia spp., Eubacterium rectale, and
Ruminococcus bromii, bacteria that metabolize dietary plant polysaccharides.
- Populations of bacteria that increase in response to a high animal protein diet are
bile-tolerant microorganisms, such as Bacteroides and Clostridia.
- A high-protein diet typically also limits carbohydrate intake, which may lead to a
decrease in butyrate-producing bacteria.

37
Q

How do fats affect microbiota?

A
  • Fats: Both quantity and quality of consumed fat impact the gut microbiota composition.
  • Fat from a vegan/vegetarian diet (mono- and polyunsaturated fats), increase the
    Firmicutes:Bacteroidetes ratio, increase lactic acid bacteria, Bifidobacterium
    spp. and Akkermansia muciniphila.
  • Saturated fat increases Bilophila spp. and Faecalibacterium prausnitzii and decreases
    Bifidobacterium spp.
  • Saturated- and trans fat, predominately found in a Western diet, reduces Bacteroidetes,
    Bacteroides, Prevotella spp., Lactobacillus spp. and Bifidobacterium spp, but increases
    Firmicutes.
  • Polyphenols: High in plant-based food, increase Bifidobacterium spp. and Lactobacillus spp.
    abundance.
38
Q

What are the benefits of probiotics?

A

Produce vitamins
Help to break down otherwise non-digestable foods
Maintenance of enterohepatic circulation
Production of short chain fatty acids
Protects from pathogens

39
Q

What does the microbiota do to the immune system?

A

Microbiota regulates intestinal immune responses through both the innate and the
adaptive immune system.

40
Q

What is the definition of a prebiotic?

A

Prebiotics: A substrate that is selectively
utilized by host microorganisms conferring
a health benefit (Gibson

41
Q

Mention some prebiotics

A

Human milk oligosacharrides
CLA=conjugated linoleic acid
PUFA=polyunsaturated fatty acid
FOS=fructooligosaccharides
GOS=galactooligosaccharides
MOS=mannanoligosaccharide
XOS=xylooligosaccharide.

42
Q

What are synbiotics?

A
  • Synbiotics: Combining pro- and prebiotics in a form of synergism.
43
Q

What is complimentary synbiotics?

A

The probiotic is chosen based on specific desired
beneficial effects on the host, and the prebiotic is independently chosen to
selectively increase concentrations of the beneficial microbiota components.

44
Q

What is synergistic synbiotics?

A

The probiotic is again chosen based on specific
beneficial effects on the host, but the prebiotic is chosen to specifically
stimulate growth and activity of the selected probiotic.

45
Q

What are the expectations that must be met for calling something probiotic?

A

That microbes must be alive in an adequate number when administered.
2. Strains must be identified genetically, classified using the latest terminology, and
designated by numbers, letters, or names.
3. Appropriately sized and designed studies must be performed to designate a strain as
probiotic and using the strain(s) on the host to which the probiotics are intended.
4. Strains shown to confer a benefit for one condition may not be probiotic for another
application.
5. Strains that are probiotic for humans but are being used in animal studies should be
clearly designated as human probiotics under experimental testing.

46
Q

How can the intestinal microbiota affect the metabolism?

A
  • Regulation of bile acids
  • Production of short chain fatty acids
  • Metabolic inflammation
47
Q

What is associated with a lean phenotype?

A

Symbiosis
Controlled pathogens
Byturate producers
Balanced SCFA profile
Anti-inflammatory
Tight intestinal barrier

48
Q

What is associated with an obese phenotype?

A

Dysbiosis
Expansion of pathogens
Loss of butyrate producers
Pro-inflammatory
Leaky gut

49
Q

Is it good or bad to have a thicker mucin layer?

A

Good, epithelial cells get less affected by bacteria

50
Q

What is FMT?

A

Fecal microbiota transplantation

51
Q

Properties of an ideal prebiotic

A

Properties of an ideal prebiotic

Desirable attributes (Properties of oligosaccharides(
Active at low dosage (Selectively and efficiently metabolized
by Bifidobacterium and/or Lactobacillusspp.)

Lack ofside effects (Selectively and efficiently metabolized by beneficial
bacteria without producing gas.)

Persistence through the colon Preferably high molecular weight.
Varying viscosity (Available in different molecular weights and linkages.)

Acceptable storage and processing stability (Possess 1–6 linkages and pyranosyl sugar rings.)

Ability to control microflora modulation (Selectively metabolized by restricted microbial species.)
Varying sweetness (Varying monosaccharide composition.)

52
Q

According to WHO and FAO “probiotics may theoretically be responsible for
four types of side effects, which?

A
  1. Systemic infections
  2. Deleterious metabolic activities
  3. Excessive immune stimulation in susceptible individuals
  4. Gene transfer

Probiotics (11 decks)

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