M9 - Gram +

Question 1

list 3 major genera f Gm +ve oral bacteria

Answer 1

• Actinomyces spp.
• lactobacillus spp.
• eubcterium spp.

Question 2

after streptococci which bacteria are the most important group of bacteria involved in dental caries?

Answer 2

lactobacilli

Question 3

what shape are lactobacilli?

Answer 3

pleomorphic rods

facultative anaerobe

Question 4

what features do lactobacili have?

Answer 4

Acidogenic and aciduric

-survive and reproduce under acidic conditions pH 5.5

Question 5

what are the 3 main groups of lactobacilli?

Answer 5

• homolactic fermenters
• heterolactic fermenters
• facultative heterolactic fermenters

Question 6

what do homolactic fermenters produce?

Answer 6

• produce only lactic acid from sugar (glucose)

Question 7

name some lactobacillus species (homofermenter)

Answer 7

• L casei Gp
• L rhamnosus
• L paracasei
• L acidophilus

Question 8

what is the link between lactobacilli and carbohydrates?

Answer 8

level of lactobacilli in saliva correlates with carbohydrate intake
- associated with deep carious lesions

Question 9

as streptococci tend to fall what happens to the lactobacilli?

Answer 9

tend to increase

Question 10

lactobacilli have no major role in initiating demineralisation, important in progression once low pH established

Answer 10

true

Question 11

what is the count of lactobacillus in HIGH predicted caries activity?

Answer 11

10000+ per ml of saliva

Question 12

which lactobacilli have protective measures?

Answer 12

• L. rhamnosus milk protected pre-school children

- Lcasei and L. rhamnosus reduced S.mutans colonisation

Question 13

Actinomyces are gram +ve pleomorphic rods

Answer 13

true

Question 14

features of actinomyces

Answer 14

Major proportion of microflora

• aneraobic or facultative anaerobes
• some possess fimbriae which aid in adherence and aggregation

Question 15

where are actinomyces mainly found?

Answer 15

mainly found in the mouth in dental plaque, in tonsils crypts

Question 16

name two different species of Actinomyces in the mouth

Answer 16

• A.naesludii
• A- odontolyticus
  found in supra and subgingival plaque

Question 17

what are actinomyces historically associated with?

Answer 17

• root surface caries

Question 18

what is the effect of actinomyces naeslundii?

Answer 18

• produce extracellular slime and fructans from sucrose
• found in large numbers in dental plaque
• able to cause periodontal disease when introduced in hamsters

Question 19

describe actinomyces israelii

Answer 19

• opportunistic and most likely to cause actinomycosis

Question 20

what are the characteristics of pus?

Answer 20

thick fluid expressed from the sinuses

• known as sulphur granules
• aggregations of actinomyces filaments

Question 21

what is the treatment of actinomycis

Answer 21

long term antibiotic treatment up to 6 weeks

Question 22

propionibacteria is a gram + bacteria what does it produce?

Answer 22

propionic acid as the major fermentation product