Biofilms Flashcards
What is a biofilm?
Matrix-enclosed bacterial or fungal populations adherent to each other and/or to surfaces or interfaces
What are the 4 defining characteristics of a biofilm?
- Provides defence
- Favourable habitat
- Community
- Default mode
What are the stages in biofilm development in teeth?
- Planktonic cell: free floating bacteria. Very susceptible to antimicrobials
- Free floating planktonic cell attaches to the enamel. Forms a micro colony.
- Mature biofilms forms
What are the benefits to bacteria of being a biofilm?
- Protective environment
- Co-ordinated cellular events: bacteria can release SCFAs to “talk” to each other
- Division of labour
- EPS (extra polymeric substances) traps nutrients
- Less energy utilised
- Survival in numbers
What are the 3 requirements for biofilm formation?
- Microorganism
- Surface
- Conditioning film
What is glycocalyx?
- Slime - Composed of extrapolymeric substrate (EPS)
- Maintains a hydrated environment
- Microcolonies are organised within the glycocalyx, allows active diffusion
- Helps to maintain ‘tissue like’ integrity
- Provides a protective barrier ( against immune factors and antibiotics)
What is dental plaque?
A diverse microbial colony (predominantly bacteria) found on the tooth surface, embedded in a matrix of polymers of bacterial and salivary origin
What is the MAIN aetiologic agent associated with caries and periodontal disease?
Plaque
What type of infection is a root canal infection?
Endodontic infection
What are some examples of oral mucosal infections?
- Thrush
- Angular cheilitis
- Denture stomatitis
What is the main determinant for microbe colonisation in the oral cavity?
Saliva
What are the stages of plaque formation?
- Pellicle formation
- Pioneer bacteria colonisation
- Microcolonies and extracellular polysaccharides
- Biofilm development
- Mature plaque
Which bacteria are the ‘pioneers’ in plaque development?
Streptococcus oralis, Streptococcus mitis, Streptococcus sanguis
Describe the main stages in plaque formation listed below:
- Pioneer colonisation
- Outgrowth
- Secondary colonisation
- Climax community
- Pioneer colonisation: Streptococcus oralis, streptococcus mitis, streptococcus sanguis.
- Outgrowth: microcolony spread outwards and upwards.
- Secondary colonisation: pioneers act as a substrate, co-aggregation, specific interactions.
- Climax community: polysaccharide production, synergistic metabolic interactons, nutrients, redox potential, oxygen, pH
What type of environment do streptococcus mutant thrive in?
Acidic
