Human Microbiota Flashcards
Define microbiota
Bacteria living in and on the body
Where does bacteria reside?
Everywhere, some sterile sites (brain, lungs, blood)
Ratio of bacterial cells to human cells?
1.3 : 1
Functions of bacteria? (4)
1) Prime immune system
2) Metabolise carbs and protein
3) Induction of angiogenesis
4) Colonisation resistance
Sterile womb theory?
Microbiota acquired through vaginal delivery or microbes in the environment if C-section
In utero colonisation?
Evidence?
Bacteria acquired from colonies in placenta and amniotic fluid - weak evidence due to inappropriate controls, insufficient detection and no evidence of bacterial viability
What is responsible for microbiota development? (3)
1) Environment
2) Diet
3) Antibiotic use
At what age has a bacterial community settled?
3 years
What are the main classes of bacteria in the gut? (2)
1) Fimicutes
2) Bacteriodetes
What are the metabolic products of dietary components? Properties?
What happens if there is excess?
Gas and short-chain fatty acids (acetate, butyrate, propionate) - Anti-inflammatory, anti carcinogenic
Excess protein forms aromatic amino acids, broken to ammonia and phenols (carcinogenic)
Relationship between gut microbiota and obesity?
Evidence?
Reduced diversity of population - less Bacteriodetes
Mouse model - Obese mouse colonised by lean mouse (eating faeces), starts to lose weight
Define dysbiosis
Imbalance in normal composition of gut microbiota
Give two examples of conditions arising from dysbiosis of the colon
C. difficile
Candida infections
Risk factors for C.diff? (2)
1) Over 65
2) Prolonged antibiotic use (broad spec)
How does C. diff arise?
Absence of competition allows spores to germinate and produce toxins which break down tight junctions, epithelia less resistant to liquid flow
Treatment for mild C. diff?
PO Metronidazole 400mg 10-14/7 TDS
Treatment for moderate C. diff?
PO Metronidazole 400-500mg 10-14/7 TDS
Treatment for severe C. diff?
PO Vancomycin 125mg QDS 10-14/7
PO Fidaxomycin 200mg BD 10/7
Novel treatment idea for C. diff?
Introduction of microbiota - isolate from faeces
SIGHT Infection Control? Purpose?
Suspect Isolation Gloves and aprons Hand washing (soap and alcohol gel) Test stoll for toxins
Reduce rates of C. diff
