Biofilms Flashcards
Definition of a biofilm
Matrix associated microbial populations adherent to each other and/or to surfaces or interfaces
Biofilms are
Polymicrobial
Can be a mix of bacteria, or a mix of bacteria, fungi and viruses
In biofilms, there are
Cell - cell interactions
Adherence to a surface
Main infections caused by biofilms in tissues/fluids are
Bacteremia (blood stream infection)
UTI
Pneumonia
Sites of primary biofilm infection
Subvenous catheter
Mouth
Artificial hip implant
Five most common bacterial infections in an ICU
- Pseudomonas aergenosa
- Staphlococcus aureus
- Escherichia coli
- Coagulase-neagive staphylococci
- Enterococci
All form biofilms, can interact with each other
Biofilms have
Dispersal mechanisms, can move and help survival
Why are biofilms studied?
- Can cause disease
- Are reservoirs of contamination
- Are difficult to control
- Have economic cost
Examples of biofilm infection
Infection on heart valves
Dental decay
Implants
Examples of contamination reservoirs
Food and food preparation, tissue surfaces, surfaces, intracellular biofilms (e.g. TB tubercules)
TB tubercules are an example of
A bacterial biofilm
Biofilms are difficult to control because they require
Higher doses of antibiotics
Persister cells
Example of economic cost of biofilm
North sea steel pipes corroded by sulphate reducing bacterial biofilms
NHS costs
As well as causing respiratory disease in CF patients, pseudomonas aerugenosa also colonizes
Burns patients
Limb movement can encourage fluid flow in burns patients which helps protect from
P. aerugensosa infection
Up to 65% of infections may be
Biofilm related
How many healthcare acquired infections are biofilm related?
60%
Nosocomial
Hospital acquired infection
When an organism forms a biofilm it
Changes its gene expression
When an organism adheres to a surface it often
Upregulates pathogenicity genes