L1 - Microbiome Flashcards
Microbiome
The ecological community that shares our body
Microbiota
the microbes comprising the microbiome
(i. e., microflora)
- Bacteria
- Bacteriophages
- Viruses
- Fungi/yeasts
Dysbiosis
alteration of the relative abundance of all or part of the microbiota
number one cause of dysbiosis → antibiotics
Specialized plant carbohydrates that are thought to be growth substrates for the bacteria in the microbiome
Prebiotics
- substances that induce the growth or activity of the bacteria in the microbiome (aka probiotics)
(plant-derived carbohydrates)
What are the microorganisms called that are believed to have health benefits when consumed?
Probiotics
(bacterial cultures)
- live cultures of organisms that can be found in yogurt
These are the microbes that are permanent residents of a given non-sterile body site (i.e. normal flora, microflora)
Commensal
- good microbes
- does not cause disease
a microbe that is capable of causing disease
Pathogen
What kind of pathogen is a Pseudomonas?
Opportunistic pathogens
An organism that does not cause disease in healthy immunocompetent individuals but can cause disease in immunocompromised individuals
(can be normal flora)
- Cause disease under certain circumstances
- when relocated it can become a pathogen (ex: UTI)
What do we call it when the microbiome is established early in life and modified by diet, environment, and infectious diseases?
Signature of Microbiome
developed by age 2
It will affect how:
much a person weighs
how they behave
their development
and health in many different physiological systems
What’s the difference between Commensal vs Pathogens?
commensals –> recognized and tolerated by IS
virulent pathogens –> attacked by IS
The immune system is shaped by early life exposures to microbial life
True or False
Early exposure, when babies are born, will shape their Immune response
True
gram (-) of bacteria plays an important role in activating immune response
What are the Commensal Functions?
- Play a role in activating IR
- Necessary for basic development and regulation of IR
- Bacteria produce key metabolites - (vitamins)
- Bacteria produce amino acids (eg; tryptophan) that can affect levels of serotonin and other neurotransmitters
- Bacteria have different “metabolic rates”
–> some are more or less efficient
–> can result in obesity
- Contain polysaccharide-digesting enzymes that are not present in the human genome
- Dietary polysaccharides are degraded in the gut by bacteria
- Colonize GI tract & inhibit growth and penetration of pathogens
- Make vitamins
- Tolerize the immune system
Commensals
Name some diseases influenced by the Gut Microbiome
Obesity
Autoimmune disease
Allergy
ASD
Depression
Anxiety
GI disease
Heart disease
Infection
Where does the microbiome come from?
Intrauterine exposure (the placenta microbiome)
Birth canal (no exposure by C-section)
Shaped by diet - Orally by breast milk
Skin to skin contact
Signature microbiome established by age 2
–> By age 2 >3,000 different taxonomic groups (bacteria)
True or False
Babies born by C-section have normal microbiome exposure like vaginal birth babies
False
they have no exposure by C-section
For every cell in your body there are how many bacterial cells?
- 1
- 0
10
1,000
10 to 100
What does your microbiome consist of?
bacteria
eukaryotic cells
endogenous viruses
and bacteriophage
- Your microbiome is not inert
Overall genetic composition, only comes from you
70%
The microbiome in the GI tract can be disturbed by:
That can result in diseases caused by:
Infection with aggressive rapid growing pathogens
(ex: cholera)
Antibiotic treatment
(kills good and bad bacteria)
Diet changes
–> Dysbiosis
–> Infection with dominant pathogen
What is Clostridium difficile (C Diff)?
Where does it come from?
disruption of normal healthy bacteria in the colon
–> small % of people have Normal flora
C diff can result from
–> antibiotics
C. difficile can also be transmitted from person to person by:
–> Gram + spore-forming bacillus
How can you get it?
Fecal-oral transmission through contaminated environment and hands of healthcare personnel
What can C diff cause?
How are risk factors?
Can cause:
- Pseudomembranous colitis
(inflammation to the colon)
- toxic megacolon
- sepsis
- death
Risk factors:
Antimicrobial exposure –> major risk factor for disease Can cause dysbiosis:
Suppression of normal flora of the colon
Acquisition and growth of C. difficile (takes over and grows)
What are the antibiotics that tend to result in dysbiosis that will allow for CDiff?
Clindamycin
Penicillins
Cephalosporins
→ antibiotics increase it not suppress it
Which one of the following is the most effective way to treat antibiotic-associated colitis?
Alternate antibiotics
Fecal transplant
Probiotics
Rehydration
Yogurt
Fecal transplant
What is the relation between obesity and the microbiome?
Good bacteria (poor converters) promotes lean
- Bacteroidetes (Bacteroides)
Bad bacteria (efficient converters) promotes obese
- everything you eat gets converted into calories
- Firmicutes
(Lactobacillus, Bacillus, Mycoplasma, Clostridium, Streptococcus)
How does the microbiome affect the energy harvest?
Gut microbiota affects
- energy harvest/conversion
Obese –> Gut microbiota is disturbed
Transferred through fecal transplants
- Effects of diet on the gut microbiome
- Gut microbiota regulates host metabolic genes
Which one of the following microbes is likely to predominate in the microbiome from an obese person?
Bacterium, good energy harvester
Bacterium, poor energy harvester
Pathogenic bacterium
Yeast
Bacterium, good energy harvester
Bacterium, good energy harvester –>
Bacterium, poor energy harvester –>
- the most efficient energy harvest from substrates by bacteria will lead to weight gain
- will not process substrates to yield more calories
(pathogens and yeast not linked to obesity)
What roles do microbes have in metabolism?
Synthesize essential amino acids and vitamins
Process indigestible components (e.g. plant polysaccharides)
Can regulate host metabolic genes
When the microbiota regulates host metabolic genes
What is the result of the normal microbiota vs the dysbiosis (altered) microbiota?
Plant polysaccharides → normal microbiota → SCFA signal → bind to GPCR 41 and GPCR 43 → results in energy balance
Dysbiosis microbiome → no signal = SCFA not produced → insulin resistant
obesity
metabolic syndrome
Normal Metabolic process vs Disrupted Metabolic process
Fermentation →
Signal for protein G3PCR 41 and 43 for normal homeostasis and metabolic function
When it’s disrupted →
you don’t have homeostasis and that can lead to type 2 diabetes, obesity and metabolic syndrome
What is the “Leaky Gut” Syndrome?
–> Result of microbes in the GI tract affecting the integrity of the intestinal barrier in the epithelial cells in the intestinal tract, breaking them apart, loosening the tight junctions so compounds can escape GI tract
Damage to intestinal wall mediated by diet infection and drugs results in escape of:
- toxins
- microbes
- undigested food
Thought by some to because of a range of chronic diseases including:
- diabetes
- lupus
- multiple sclerosis
- migraines
- autism
If dysbiosis, inflammation, and leaky gut can occur resulting in:
→ Toxins, organism, undigested food, medications, metabolites, can leak out
IR produces potential widespread effects
- can cross the blood-brain barrier and result in neurological effects:
diabetes
asthma
lupus
multiple sclerosis
depression
anxiety, autism
What is the relationship between Autism spectrum disorders and the GI
- ASD patients often have GI sypmtoms
Certain bacteria are over-represented in ASD gut microbiome
Clinical improvement has been reported in ASD patients who
- Developed fever
- Given antibiotics
- Ingest probiotics
Normal flora is found in all but?
Genitourinary
Oral Cavity
Optic Cavity
Nares
Optic Cavity
True or False
Fungi are not part of our microbiome.
False
- Bacteria
- Bacteriophages
- Viruses
- Fungi/yeasts
Are all part of microbiome
To enhance the growth of the good bacteria in your gut microbiome, what would you eat?
Yogurt
Fiber
Probiotic Pills
Poopsicles
Fiber
Remember: induced growth is by prebiotics
The main cause of dysbiosis is?
Diet Change
Prebiotics
Probiotics
Antibiotics
Antibiotics
Clostridium species would classify as what?
Good bacteria - poor harvest
Good bacteria - efficient harvester
Bad bacteria - poor harvester
Bad bacteria - efficient harvest
Bad bacteria - efficient harvest
What are some examples of Commensals?
E. Coli
Pseudomonas –> can cause UTI
How much gut bacteria can an individual have?
Over 1,000 species
160 species/individual
>99% of gut microbiome
Makes up:
2-3 lbs of microbes in the human body
Name the good vs bad bacteria in body
Harmful Bacteria
Clostridia
–> production of entertoxins
Good Bacteria
Lactobacillus
Bifidobacterium
Campylobacteriojejum
Good bacteria –> (poor converters) –> lean
Bad bacteria (efficient converters) –> obese
Good bacteria/poor convertors
will not break down everything and thus will not absorb all the glucose
- Bacteroidetes
Bacteroides
Bad bacteria/efficient converters
break down and convert everything eaten resulting in obesity
Firmicutes•Lactobacillus, Bacillus, Mycoplasma, Clostridium, Streptococcus
How can the Microbiome affect and result in ASD?
women who suffer from a high, prolonged fever during pregnancy are up to seven times more likely to have a child with autism
40 to 90 % of all children with autism suffer from gastrointestinal symptoms
- Dysbiosis has been noted in gut
- Neuroinflammation
In Autism,
we see an increase in
we see a decrease in
Clostridia
Lactobacillus
In Type 2 Diabetes,
we see an increase in
we see a decrease in
Clostridia
Lactobacillus
In Alzheimer’s, we see an increase in
Clostridia
