Biofilms Flashcards
What is a Biofilm?
A group of microoganisms which are adherent both to each other and to a surface
What are the THREE main stages of Biofilm formation?
- Attachment
- Growth
- Detachment
What is the biofilm matrix made from?
- Polysaccharides
- Proteins
- Nucleic acids
A polymicrobial biofilm is comprised of:
a) A polymer encased pathogenic bacterium
b) A polysaccharide encased oppotunistic pathogen
c) Multiple species of bacteria, fungi, or both
d) Bacteria in their planktonic state
c) Multiple species of bacteria, fungi, or both
The extracellular matrix of biofilms is comprised of:
a) Proteins and extracellular DNA
b) Polysaccharides and intracellular RNA
c) Peptidoglycan and messenger RNA
d) None of the above
d) None of the above
Usually comprised of different polysaccharides, proteins & nucleic acids
What are some entry points on the human body for microbial biofilms?
- Catheter
- Hip replacement
- Peridontal disease
Do biofilms contain one or two species of bacteria, or many species?
Many species
(Polymicrobial)
Dental plaque is an example of a polymicrobial biofilm
What bacteria forms biofilms in aquatic environments prior to entry into a host?
Vibrio cholerae
Where does the opportunistic pathogen Pseudomonas aeruginosa form biofilms?
In the airways of cystic fibrosis sufferers
What type of biofilms for fungi make?
Hyphal
Why is the formation of biofilms important?
- Promotion of bacterial survival
- Permitting bacteria to remain in favourable niche
- Close proximity with the biofilm provides more opportunities for nutrient and genetic exchange between organisms
Do bacteria grow more quickly or more slowly than their planktonic counterparts?
More slowly
How do bacteria in biofilms differ in gene expression than planktonic cells?
Enhanced expression of genes conferring tolerance to antimicrobial substances
What is the mechanism for biofilm formation?
- Attachment of planktonic cells to a surface (using pili, flagella, adhesin proteins)
- Colonisation and cell-cell adhesion by the extracellular matrix
- Proliferation and maturation, further matrix production
- Dispersal to release planktonic cells; this may be triggered by nutrient availability or other environmental factors
What are some strategies for the control of biofilm formation?
- Inhibition of regulatory systems that control biofilm formation through low molecular weight molecules
- Use of enzymes that degrade the components of the extracellular matrix
