Biofilms - Microbial Ecology of the Mouth Flashcards
what is a biofilm?
matrix enclosed bacterial (or fungal) populations adherent to each other and/or to surfaces or interfaces
what are biofilms generally made of?
bacteria
what do the bacteria in biofilms produce?
a glue which is important for protecting it from saliva and antibiotics and innate immune response, therefore making the glue an immune defence
what are the defining characteristics of the biofilm?
immune defence and very difficult to clinically manage these infection types with an antimicrobial
what are planktonic cells?
free floating cells
what are the benefits of being a biofilm?
protective environment, co-ordinated cellular events, division of labour, EPS traps nutrients, less energy utilised, survival in numbers, bacteria can sense one another
what is needed for a biofilm development?
surface, conditioning film and micro-organism
what are the stages of biofilm development?
adhesion, colonisation, accumulation, complex community and dispersal
what is the glycocalyx extra-cellular matrix composed of?
exopolymeric substrate
what does the glyocalyx extracellular matrix do?
maintains a hydrated environment, helps maintain a tissue-like integrity and provides protective barrier
what does the organisation of microcolonies within the glycocalyx extracellular matrix allow?
active diffusion
what features of immune resistance does the glycocalyx extracellular matrix give?
blocks phagocytosis, covers complement activation sites on the bacterial surface, inhibits chemotaxis, decreased natural killer cell function, prevents diffusion of bacterial products, immune complexes - frustrated immunity
how does the glycocalyx extracellular matrix have antibiotic resistance?
prevents diffusion of antibiotics, acts as ion-exchange barrier, binding charges molecules, thickness and complexity, physiological state of the bacteria, low growth rates, differential gene expression
what is dental plaque?
a diverse microbial community found on the tooth surface, embedded in a matrix of polymers of bacterial and salivary origin
where is dental plaque found?
at protected and stagnant surfaces, and these are at greatest risk of disease
how does dental plaque form part of the defence system?
it helps to prevent colonisation of enamel by exogenous microorganisms
what are the 2 different types of caries?
root surface caries and coronal caries
name an endodontic infection
root canal
what are the 2 periodontal infections
gingivitis and periodontitis
where does oral malodour originate from?
dorsal surface of the tongue
name 3 mucosal infections
thrush, angular chelitis, denture stomatitis
what are the 4 stages of plaque development?
pioneer colonisation, outgrowth, secondary colonisation, climax community
what happens in the outgrowth stage of plaque development?
microcolony spread outward and upward
what happens in the secondary colonisation stage of plaque development?
pioneers act as substrate, co-aggregation, specific interactions
