Biofilms and humans Flashcards
Why do the effect of antibiotics differ from lab and in vivo?
In the lab, scientists often use planktonic growth methods to grow biofilms.
These are grown in a liquid unattached to a surface, under artificial conditions.
Since there are phenotypical differences in the plankton and the bacteria, the experimental conditions don’t mimick the real world.
When were biofilms first described?
In the 70s
What have biofilms taught us?
The complexity of bacteria
Why do biofilms interest us?
More resistant to antibiotics
Protective niche
Ability to gene transfer
Found in many systems
Diseases involving biofilms
Anything added exogenously from the inside and implanted on the body has potential to cause infection
Lung infections accompanying cyctic fibrosis Joint prostheses Heart valves Root canal infections Catheter-associated infections
Where were biofilms first demonstrated?
In airways of patients with cystic fibrosis
Steps of biofilm formation
- Reversible adsorption of bacteria
- Irreversible attachment of bacteria
- Growth and division of bacteria
- Exopolymer production and biofilm formation
- Attachment of other organsims to the biofilm
Why do we consider biofilms complex?
They are similar to coordinated simple organisms
Can have reproductive system
Can have circulatin systems where the nutrition is taken in and wastes taken out
What are the mechanisms of biofilm antimicrobial resistance?
Matrix formation
Quorum sensing
Slow growth rate
Some bacteria produce enzymes that break down drug toxins
Multi-drug efflux pump
Short-term decreased membrane permeability
Persister cells
Why and how does reversible adsportion of bacteria happen during biofilm formation?
Electrostatic bonds
Pilli and Flagella check to see if the environment is suitable
How are irreversible attachments of bacteria made in biofilm formation?
Via hydrogen bonds
Gives rise to preferential positioning of bacteria species on surfaces.
What are persister cells?
Cells that lay on the bottom of biofilms.
Activate on exposure to toxin (bleach) to repopulate the biofilm and remove the toxin.
What is the biofilm matrix made of?
Exopolysaccharide
