Human Microbiome Flashcards
What is a microbiota?
The microbial taxa of organisms that reside in or on a host or specified part of a host
- A list of species
What is a microbiome?
Collective genomes of all the organisms that reside in or on a host
- A list of genes
What part of the body are hotspots for microbial life?
Nasal tract Oral tract Skin Gastrointestinal tract Urogenital tract
What are the three stages of life in which our microbiota is introduced?
As a fetus
As an infant
As a toddler
How do we gain microbiota as a fetus?
Gut microbiota of mother
Vaginal infection of mother
Vaginal or cesarean delivery
How do we gain microbiota as an infant?
Through milk consumption
Antibiotics
Environment
Solid food introduction
How do we gain microbiota as a toddler?
Diet
What are the main two microbial groups found in and on our body?
Bacteroidetes
Firmicutes
What are the features of bacteroidetes?
Gram negative
Anaerobic
Non-spore forming
What are bacteroidetes specialists at degrading?
High molecular weight organic matter
- Proteins and carbohydrates
What is the main human genera of bacteroidetes?
Bacteriodia
What are the features of firmicutes?
Gram positive
Cocci or rod
Range of oxygen sensitivities
What do firmicutes produce?
Short chain fatty acids
What are the main human genera of firmicutes?
Clostridia
Bacilli
Mollicutes
What is the main route of entry for inhaled microbes?
Nose
What is the primary defence in the nose?
Mucociliary clearance = motile cilia
What are the secondary defences in the nose?
Secretion of antimicrobial peptides and reactive oxygen species
What are the two main microbiota in the nasal tract?
Firmicute = forms biofilms that coat the nasal lining Actinobacteria = promote release of fatty acids
What are the natural host defences to pathogen entering through the nose?
Mucous
Cilia
What are the natural host defences to pathogens entering through the mouth?
Saliva
pH
Change in temperature
Host immune system
What are the predominant microbiota in the mouth?
Fimicutes
Bacteroidetes
Proteobacteria
What do the microbiota found in the mouth form which acts as a barrier to pathogenic organisms?
Elaborate microbial scaffold
What are the natural host defences to pathogens on the skin?
Sweat = acidic
Antimicrobial properties
What are the predominant microbiota found on the skin?
Firmicutes
Actinobacteria
What are the natural host defences to pathogens in the intestine?
Low pH
Bile
Immune system
Mucus
What are the predominant microbiota found in the intestine?
Bacteroidetes
Firmicutes
How does an individuals microbial composition vary?
With age, exposure and location along the GI tract
Why are urinary systems almost sterile?
Urine helps flush away any microbes that start to colonise
What is the predominant microbiota in the urogenital tract?
Firmicutes
What diseases may be impacted by changes in our microbiota?
IBD
Pre-term birth
Cardiovascular disease
Obesity
The proportion of what microbe decreases as we get older?
Bifidobacterium = actinobacteria
The proportion of what microbe increases as we get older?
Proteobacteria
