Biofilm Flashcards
What is a biofilm?
Breeding ground for antibiotic resistance as they change in genetic information and form a protective matrix consisting of sugar/ proteins and extracellular DNA.
What are the three stages of the formation of a biofilm:
Attachment, growth and detachment.
What type of bacteria form biofilms?
Gram positive
What type of environment does a biofilm become a mushroom strcuture?
In a hydrodynamic environment.
In a flow cell - pseudomonas aeruginosa forms mushroom in lab.
What type of environment does a column and canopy structure form?
In space, microgravity static environment.
Are biofilms polymicrobial?
Yes, biofilms may contain only one or two species of bacteria but more commonly many species are formed (mixed biofilm)
What is an example of a pioneer bacteria?
S. gordonii, S.oralis
What are some surfaces in which microbial biofilms form?
Medical devices, inert surfaces to include water systems and pipework.
Where does Vibrio Cholerae form biofilms before entry into a host?
In aquatic environments.
It also changes DNA before entering the host becoming more virulent.
What pathogen forms biofilms in the airways of cystic fibrosis sufferers?
The opportunistic human pathogen Pseudomonas Aeruginosa - in the mucus of the lungs.
What are three reasons why biofilms are important?
- survival
- remain in favourable niche
- close proximity to nutrients and other genetic material exchanges.
How are biofilms able to TOLERATE antimicrobial substances?
- reduced penetration, biofilm structure
- bacteria grows slower
- different gene expression with enhanced expression of genes conferring tolerance to antimicrobial substances.
How can bacteria influence other cells in biofilm community?
Through both chemical and physical interactions.
What is the mechanism (3 - step) to the formation of the microbial biofilm?
- Attachment - planktonic cells to surface using pilli, flagella, adhesion proteins.
- Colonisation and cell-cell adhesion by the extracellular matrix (maturation)
- Dispersal: may be triggered by nutrient by nutrient availability or other environmental factors.
What blocks Quorum sensing?
Furanone C30
What are 3 of the strategies used for the control of biofilm formation?
- Inhibition of regulatory systems that control the formation trough low molecular weight molecules.
- DNASes
- Enzymes
What can rapid dispersal of biofilms do?
This can be aggravating as it can quickly disseminate large numbers of bacteria into the bloodstream.
How (3) are biofilms found in the lab?
- High throughput screening
- Metagenomic BioDiscovery ex: marine sponge
- Mining Microbe speak
- Immobilisation
What is mining ‘microbe speak’?
This is when microbial compounds can be blocked in the biofilm in co-colonising pathogens.
Clinical isolates sensitive to small molecule analogues
What is the most common signal bacteria use to contact eachother?
3-oxo-C12
What does pseudomonas mainly use to communicate with each other?
HHQ - heptylquinoline
What is the chemical form of communication used specifically by aeruginosa pseudomonas?
4-Alkylquinolones
What is the inhaled/nebulised antibiotic used along with Furanone C30 to block Quorum Sensing?
Tobramycin
