Gut microflora & Biofilms Flashcards
Role of the GI microbiota?
• produces enzymes - key in the breakdown of dietary compounds
• lactic acid bacteria (b12)
• produce bacteriocins (kill other bacteria)
• bacterial competition
What causes changes in the microflora?
The use of antibiotics, chemotherapy and infection
What are the consequences of change in the Microflora?
- increased risk of infection and allergy
- can lead to IBD
Examples of species of GI Biofilm?
• E.coli
• clostridium
• bifidobacterium
What are the 2 types of bacterial competition?
Interference - antagonist factor to block competitors
Explorative - preventing competitors from gaining access to resources
Definition of Biofilms
A community of slimy microbes living on a surface
Examples of biofilms?
• dental plaque
• slime on rocks in stream
• mucous membrane
• soap scum on bath
Development of biofilms?
• microbes attach to a surface
• produce a extra cellular matrix
• creates environment for other cells
• they secrete Quorum sending molecules
• new cells arrive and join the biofilm and other leave
What is the purpose of Quorum sensing?
• allows communication between bacteria
• as the number of cells increase, the conc of this sensing molecule also increases
What happens when QS is disrupted?
Inhibits formation of biofilm
When happens when QS is amplified?
It allows the bacteria to be revealed to hosts immune system, before infection takes place
How can probiotics protect against disease?
• enhance epithelial barrier
• modulate immune system
• compete with pathogens
• produce antimicrobial substances
• increases binding to mucosa
Other uses of Probiotics
- protect against H.pylori
- reduce symptoms of IBS
- prevent allergies/intolerance
Disadvantages of using Probiotics?
- can causes septicaemia & bacteraemia
- can cause fungalemia
- increase sensitivity to allergens
- trends of obesity (high sugar content in yoghurts)
- bacteria can be killed by stomach acid
