Microbiology

Question 1

Name 2 key virulence factors of strep mutans that are used to influence enamel dissolution

Answer 1

Adhesion
High tolerance to acidic environments

Question 2

What are 3 features of an ECM that make them resistant to anti-microbials?

Answer 2

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

Question 3

What type of bacteria is strep mutans?

Answer 3

Gram positive anaerobe

Question 4

Name 2 periodontal micro-organisms

Answer 4

P. Gingivalis
T. Forsythia

Question 5

Name 2 caries micro-organisms

Answer 5

Strep mutans
Lactobacillus bacteria

Question 6

What is virulence?

Answer 6

The ability of an organism to infect the host and cause disease

Question 7

What are virulence factors?

Answer 7

Molecules that assist the bacterium to colonise the host at a cellular level

Question 8

What are 2 key virulence factors used by strep mutans to influence enamel dissolution?

Answer 8

Adhesion
High tolerance to acidic environments

Question 9

What type of bacteria is P. Gingivalis?

Answer 9

Gram negative, non-motile, anaerobe

Question 10

What are some virulence factors of P. Gingivalis?

Answer 10

Fimbriae - finger-like projections that assist with adhesion

Has a “cocktail of degradative enzymes”

Endotoxin (LPS) - induces inflammation and immune response

Question 11

What are some general influences on the oral microflora?

Answer 11

Host factors - inc. OH and disease
Diet
Saliva
Gingival crevicular fluid
Microbial interactions
Gaseous environment (oxygen concentration)

Question 12

How does P. Gingivalis manipulate host defences?

Answer 12

Gingipains - degradation of cytokines

Induction of tissue destruction through activation of MMP’s

Question 13

What are 2 systemic diseases related to perio disease?

Answer 13

Rheumatoid arthritis
Atherosclerotic plaque and cardiovascular disease

Question 14

What are the stages of colonisation of a biofilm?

Answer 14

Adhesion
Survival and growth - micro-colonisation
Biofilm development
Mature plaque complex formation

Question 15

What are 3 things needed for successful colonisation?

Answer 15

Adherence
Substrate
Liveable environments

Question 16

What group of bacteria is prevalent in PRIMARY endodontic infections?

Answer 16

Generally polymicrobial
BUT
DOMINATED BY gram negative anaerobes

Question 17

What bacteria is likely to be present in secondary endodontic infections and what is one of its key virulence factors?

Answer 17

E. Faecalis
Adhesin

Question 18

How do you determine cause and effect of a disease?

Answer 18

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.

Question 19

Why is it important to differentiate between candida albicans and candida glabrata in denture induced stomatitis?

Answer 19

Candida glabrata is insensitive to AZOLES

Question 20

What type of diagnostic test can be done to identify culprit organism of a disease?

Answer 20

Selective agar testing

Question 21

What are anaerobes sensitive to?

Answer 21

Metronidazole

Question 22

What testing method would identify bacteria within a clinical sample?

Answer 22

DNA probes

Question 23

How would you take a periodontal specimen?

Answer 23

Paper points from gingival crevice at site of inflammation (go to deepest pocket/ worst site of inflammation)