4.2 Microbiota Flashcards
What is microbiota ?
community of microorganisms that inhabit a particular environment, such as the human body or a specific ecosystem
What is the microbiome ?
collective genomes of the micro-organisms in a particular environment (collection of all their genetic material - RNA/DNA)
What parts of the human body do microorganisms inhabit ? where is vast majority ?
- gastrointestinal tract
- skin
- saliva
- oral mucosa
- conjunctiva
- vast majority in colon
The microbiome plays a critical role in human health, supporting processes such as what ?
- maining intestinal integrity and supporting barrier function
- Breaking down food
- Providing essential vitamins, nutrients and beneficial short-chain fatty acids such as butyrate
- Regulating the immune system
- Protecting against infection through secretion of bacteriocins and antagonising pathogens
- Contributing to mental health
- Regulating metabolism
What are the methods of microbiota acquisition in babies ?
- vertical = transferred from parent to offspring
- horizontal = microbial colonisation after germination/birth/hatching from environment or conspecifics
- or combination of both
What are the 4 dominant gut microbial phyla ?
Firm Bacteria Are Powerful
- Firmicutes
- Bacteroidetes
- Actinobacteria
- Proteobacteria
How is dysbiosis often defined as?
an alteration of gut microbiota composition and a cause or a consequence of disorders
Example of genus of bacteria included in the phylum firmicutes
- lactobacillus
- bacillus
- clostridium
- streptococcus
- enterococus
- ruminococus
Example of genus of bacterium in phylum bacteroidetes
- bacteroides
- prevotella
example of genus of bactiera in actinobacteria phylum
bifidobacterium
example of bacteria in proteobacteria phyla
- escherichia coli
- helicobacter pylori
- enterbacterias
- campilobacterias
List the types of microorganisms found in the human microbiota
- bacteria
- viruses
- fungi
- archea
- protozoa
The viruses found in the human microbiota are predominantly ….1… which .2… and …3.. within bacterial cells
- bacteriophages
- infect
- replicate
Most common fungi species that is found in the human microbiota ?
candida
Example of archea that is found in the human microbiota and what it is
methanobrevibacter, type of methanogen helps with host’s nutrient break down
Function of firmicutes ?
- break down complex carbohydrates
- regulate immune system
- promote integrity of the git barrier
- fermentation of dietary fiber
- synthesis of vitamins like vitamin K
- Firmicutes break down complex carbohydrates producing what ?
- Give examples of the answer above
- short chain fatty acids (SCFAs)
- acetate, propionate, butyrate
Function of bacteriodetes ?
1. metabolise…
2. contribute to…
3. maintenance of..
- metabolise plant polysaccharides and dietary fiber
- contribute to production of SCFAs in immune modulation
- mainetenance of intestinal homeostasis
Function of actinobacteria?
- ferement carbohydrates
- produce lactic acid
- compete with harmful bacteria for resources in the gut
- maintenance of a balanced gut microbiota
- support immune function
Phylum proteobacteria include many ..1.. species, some ..2.. and play important roles in gut health.
They can produce SCFAs and contribute to the breakdown of …3..
- pathogenic
- commensals
- complex carbohydrates
list examples of genera that most bacteria belong to
brb pc fep
- bacteroides
- clostridium
- fusobacterium
- eubacterium
- ruminococcus
- peptococcus
- peptostreptococcus
- bifidobacterium
Which genera are present to a lesser extent for bacteria ?
- escherichia
- lactobacillus
- Which genus is suggests to be especially important in the functioning of the host ?
- why is this ?
- bacteroides
- species from the genus alone constitue about 30% of all bacteria in the gut
What are the 4 main functions of gut microbiota ?
- promotes digestion by facilitating the absorption of nutrients
- helps the digestive tract to function properly
- creates a barrier against pathogens and toxins
- plays a defensive role in the development of the immune system
In vertical transmission of microbiota to baby, what are the 2 main sources of microbiota for the baby ?
- mother’s vaginal bacteria
- mother’s gut bacteria
‘mother’s vaginal bacteria’ as a source of microbiota for the baby:
[GBS = Group B Streptococcus]
Onset of labor leads to ..1….
GBS bacteria travels up the vagina to ..2..
GBS bacteria can also transfer as baby moves ..3.. during labour
..4… of GBS bacteria into baby’s lungs
- rupturing of membranes
- amniotic fluid
- down birth canal
- aspiration
Vertical transmission: mother’s gut bacteria
Baby exposed to GBS bacteria from contact with ?
maternal fecal mattering during birth process
Why would having a C-section rather than a vaginal delivery impact the microbiota of the baby ?
Certain vaginal and gut bacteria from the mother are transferred to the baby via vertical transmission, which occurs during vaginal delivery.
What are the other names for group B streptococcus ?
- Streptococcus agalactiae
- Strep B
- beta haemolytic strep
What is beta hemolysis ?
complete lysis of red blood cells
some bacteria produce .1… enzymes which ..2.. leading to lysis of RBCs
e.g. ..3.. is a beta-hemolytic bacteria
- hemolysin
- break down hemoglobin in RBCs
- GBS
Why is beta hemolysis important in microbiology ?
It’s a diagnostic tool
what will beta haemolytic bacteria produce on blood agar mediums ?
produce clearing on blood agar mediums around the bacterial colonies on samples in the lab
What gram staining does the bacteria group B streptococcus have ? & what is GBS also known as ?
gram positive
beta hemolytic bacteria
What is GBS the common coloniser of ?
human gastrointestinal and genitourinary tracts
Which year was GBS recognised as causing disease in humans ?
1930s
GBS can cause severe disease in what demographics of people ?
- young infants
- pregnant women
- older adults
- immunocompromised or immunosuppresed adults
What did GBS emerge as in the 1970s ?
most common cause of sepsis and meningitis in infants < 3 months
What condition can GBS lead to in minority of newborns ?
early-onset GBS disease leading to early-onset sepsis, pneumonia or meningitis
GBS early-onset disease:
1. onset when in life ?
2. acquired by fetus when ?
- first week
- in utero or during birth
GBS early-onset diseases is leading causes of …1… in neonates and also causes …2.. and ..3…
- sepsis
- penumonia
- meningitis
GBS late-onset disease (LOD) usually occurs ….1… after birth, but may occur up to ..2… of life
It has a wider ..3… than GBS early-onset disease (EOD) (sepsis, pneumonia , meningitis )
- 1-4 weeks
- 3 months
- clinical spectrum
GBS Late-onset disease (LOD) may cause ?
- meningitis
- sepsis
- pneumonia
the ones below aren’t caused by early onset GBS as well !
* septic arthritis
* osteomyelitis
Name one of the major factors involved in horizontal transmission of microbiota
diet
What types of microorganisms found in gut microiome ?
- symbiotic organisms
- opportunistic pathogens
- commensal organisms
By what age do people have adult-like microbiota
1-3 (toddler)
What changes to diet is a reason for gut microbiota dysbiosis ? [alter]
- high-protein diet
- high-salt diet
- high-fat diet
- high-sugar diet
What are drug related a reasons for gut microbiota dysbiosis ? [alter]
- antibiotics
- antitumour drugs
- immunosuppressants
What are enviromental pollution related reasons for gut microbiota dysbiosis ?
- atmospheric particulate
- heavy metals
- microplastics
- pesticides
What are other factors apart from diet, drug and enviromental pollution that are reasons for dysbiosis ?
- age
- diseases
- habit
- genes
What can antibiotics do to microbiome ?
They can alter the population structure of the microbiome
Antibiotics can alter the population structure of the microbiome
the ..1… structure of such microbiomes is recovered after some time, the ..2… structure is not fully equivalent
- overall
- genomic
What are probiotics ?
live microorganisms that are intended to have health benefits when consumed or applied to the body
..1… types of probiotics may have ..2.. effects
1 = 2 = different
What are prebiotics ?
nondigestible food components that selectively stimulate the growth or activity of desirable microorganisms
What are synbiotics ?
products that combine probiotics and prebiotics
Advantages of probiotics
- oral application
- restoration of good bacteria and gut barrier
diadvantage of probiotics
- oral dose that reaches the gut varies
- potential loss of adaption of culture-derived probiotics in the gut
What is fecal transplantation (or bacteriotherapy) ?
transfer of stool from a healthy donor into the gastrointestinal tract for the purpose of treating recurrent
Succes rate of ~ ….. % when FMT (fecal transplantation) is used to treat recurrent Clostridium difficile infection (CDI)?
90
advantage of FMT (fecal microbiota transplantation) ?
- safe application
- simple procedure
disadvantage of FMT (fecal microbiota transplantation) ?
1. impact ?
2. effectiveness with IBD
3. what is important ?
- variable impact
- not very effective in IBD
- quality of donor stool is important
Changing the environment microbial status can either ..1… or ..2..
- promote disease
- confer protection
advantage of environment as symbiotic intervention ?
- early-life exposure to microbes improves later-life immunity
disadvantage of environment as symbiotic intervention ?
- not qualitative / quantitative
- mechanisms of effect unknown
A biofilm = ….1.. enclosed by an …2… materials such as mineral crystals, …3… & other substances
- microbial community
- extracellular
- blood
Where do biofilms form ?
- tissue
- medical devices
- surfaces
What are biofilms environments for ?
genetic exchange
> 80% of microbial infections are related to what according to national institute of health ?
biofilms
bacteria within ..1.. have increased ..2.. to antimicrobial drugs
- Biofilms
- resistance
List 4 types of biofilms
- dental plaques
- GI
- cystic fibrosis
- medical implants
