Microbiology Flashcards
Name 2 key virulence factors of strep mutans that are used to influence enamel dissolution
Adhesion
High tolerance to acidic environments
What are 3 features of an ECM that make them resistant to anti-microbials?
Enzymes neutralise antimicrobials
Biofilm acts as a physical barrier - hinders penetration of Ab and may prevent accumulation of bactericidal concentration throughout the entire biofilm
Efflux pumps - ECM can pump out antimicrobial agents from cells reducing their effectiveness
What type of bacteria is strep mutans?
Gram positive anaerobe
Name 2 periodontal micro-organisms
P. Gingivalis
T. Forsythia
Name 2 caries micro-organisms
Strep mutans
Lactobacillus bacteria
What is virulence?
The ability of an organism to infect the host and cause disease
What are virulence factors?
Molecules that assist the bacterium to colonise the host at a cellular level
What are 2 key virulence factors used by strep mutans to influence enamel dissolution?
Adhesion
High tolerance to acidic environments
What type of bacteria is P. Gingivalis?
Gram negative, non-motile, anaerobe
What are some virulence factors of P. Gingivalis?
Fimbriae - finger-like projections that assist with adhesion
Has a “cocktail of degradative enzymes”
Endotoxin (LPS) - induces inflammation and immune response
What are some general influences on the oral microflora?
Host factors - inc. OH and disease
Diet
Saliva
Gingival crevicular fluid
Microbial interactions
Gaseous environment (oxygen concentration)
How does P. Gingivalis manipulate host defences?
Gingipains - degradation of cytokines
Induction of tissue destruction through activation of MMP’s
What are 2 systemic diseases related to perio disease?
Rheumatoid arthritis
Atherosclerotic plaque and cardiovascular disease
What are the stages of colonisation of a biofilm?
Adhesion
Survival and growth - micro-colonisation
Biofilm development
Mature plaque complex formation
What are 3 things needed for successful colonisation?
Adherence
Substrate
Liveable environments
What group of bacteria is prevalent in PRIMARY endodontic infections?
Generally polymicrobial
BUT
DOMINATED BY gram negative anaerobes
What bacteria is likely to be present in secondary endodontic infections and what is one of its key virulence factors?
E. Faecalis
Adhesin
How do you determine cause and effect of a disease?
If one bacteria causes a disease, then removal of culprit organism should lead to resolution of disease.
If disease persists after removal of bacteria then not sole cause.
Why is it important to differentiate between candida albicans and candida glabrata in denture induced stomatitis?
Candida glabrata is insensitive to AZOLES
What type of diagnostic test can be done to identify culprit organism of a disease?
Selective agar testing
What are anaerobes sensitive to?
Metronidazole
What testing method would identify bacteria within a clinical sample?
DNA probes
How would you take a periodontal specimen?
Paper points from gingival crevice at site of inflammation (go to deepest pocket/ worst site of inflammation)
