Biofilms Flashcards
What is a biofilm?
Microbial aggregates in an EPS matrix, attached to surfaces or each other.
Name 3 components of the EPS matrix.
-Polysaccharides
-eDNA
-Proteins/lipids.
What are the stages of biofilm development?
-Attachment → irreversible attachment → maturation → dispersal.
Why are biofilms hard to treat with antibiotics?
EPS blocks drug penetration, cells are dormant (persisters), and resistance genes spread via horizontal transfer.
What is quorum sensing?
It is cell communication via signalling molecules to coordinate virulence, EPS production, etc.
How does horizontal gene transfer occur in biofilms?
By conjugation/plasmid transfer between dense, surface-attached cells.
Name 3 medical devices prone to biofilm infections.
-Catheters
-Prosthetic joints
-Pacemakers.
Why might biofilm infections be culture-negative?
Bacteria are dormant, fastidious, or embedded in EPS/host tissue.
What is FISH used for in biofilm diagnosis?
Fluorescently labels bacterial RNA/DNA to visualize clusters in samples.
What are persister cells?
Dormant, antibiotic-tolerant subpopulations in biofilms.
Name two strategies to disrupt biofilms.
-EPS-degrading enzymes (e.g., DNase).
- Nitric oxide (induces dispersal).
Why is physical removal often needed for biofilm infections?
Biofilms resist drugs; implants/foreign bodies must be excised.
How do biofilms benefit from heterogeneous niches?
Creates micro-environments for resource sharing and stress tolerance.
What is a common emergent property of biofilms?
Increased virulence or antibiotic resistance via quorum sensing.
