Resident Oral Microbiota

Question 1

non-selective medium

Answer 1

blood agar

Question 2

selective medium

Answer 2

mitis salivarius bacitracin agar sabouraud agar- specific for yeasts rogosa plate - specific for lactobacilli CFAT agar plate- selective for actinomyces spp.

Question 3

what are steps of the gram stain

Answer 3

fixation crystal violet iodine acetone safranin FryChipsInASchool

Question 4

colour of gram +ve cells

Answer 4

purple

Question 5

colour of gram -ve cells

Answer 5

pink

Question 6

Streptococci – ……….. possitive

what are the primary colonisers of the oral environment

Answer 6

Gram-positive cocci, -haemolytic catalase negative

S. salivarius: early colonizer of mouth

S. oralis & S. mitis: ubiquitous

S. sanguinis: colonizes teeth

S. mutans & S. sobrinus: caries

Question 7

features of streptococci

Answer 7

gram + cocci alpha haemolytic catalase -ve

Question 8

which streptococci are found in mouth and what are they associated with

Answer 8

streptococcus oralis= health streptococcus mitis= health streptococcus sanginis= health streptococcus intermedius= abscesses streptococcus mutans= caries streptococcus sobrinus= caries

Question 9

features of actinomyces

Answer 9

opportunistic pathogens, common in dental plaque gram+ branched rods

Question 10

gram + rods examples

Answer 10

actinomyces (plaque) eubacterium (plaque) lactobacillus (dental caries)

Question 11

gram + rods examples

Answer 11

actinomyces (plaque) eubacterium (plaque) lactobacillus (dental caries)

Question 12

gram - rods examples

Answer 12

actinobacillus fusobacterium (plaque) porphyromonas prevotella treponema (periodontal disease)

Question 13

what is the basis of molecular taxonomy/ molecular typing

Answer 13

differences in variable region of 16S ribosomal RNA genes no mutations occur in the essential regions

Question 14

16s ribosomal RNA gene bp number

Answer 14

1500bp

Question 15

what is the basis of DGGE- denaturing gradient gel electrophoresis

Answer 15

1. PCR amplify variable sequence via primer with a GC-CLAMP 2. separate products via electropheresis on a gel with LOW to HIGH denaturation gradient of urea and temperature 3. amplimers with LOWER GC CONTENT= denature at lower temperature, higher GC content amplifiers will run further down the gel

Question 16

features of microorganisms on tongue are…

Answer 16

gram + streptococci rods gram- anaerobes

Question 17

features of microorganisms on lip and palate

Answer 17

gram + facultative streptococcus spp actinomyces

Question 18

features of microorganisms on lip and palate

Answer 18

gram + facultative streptococcus spp actinomyces

Question 19

features of bacteria found in SUB-gingival plaque

Answer 19

gram +ve cocci streptococci gram+ve rods actinomyces gram -ve ANAEROBIC rods fusobacterium prevotella spirochaetes

Question 20

which organisms are associated with periodontal disease but positively linked with lack of caries

Answer 20

campylobacter rectus selenomas noxia fusobacterium nucleatum

Question 21

which organisms are associated with periodontal disease but positively linked with lack of caries

Answer 21

campylobacter rectus selenomas noxia fusobacterium nucleatum

Question 22

what is meant by edentulous

Answer 22

loss of teeth also there is loss of s. sanguinis, s.mutans and strict anaerobes

Question 23

what are the primary colonisers of the oral environment

Answer 23

s. salivarius = early colonizer s.oralis= ubiquitous s. mitis= ubiquitous s.sanguinis =colonise teeth s. mutans and s.sobrinus= caries actinomyces veillonella gemella

Question 24

Actinomyces are

Answer 24

Gram positive branched rods, common in dental plaque; implicated in root surface caries; opportunistic pathogens.

Question 25

Lactobacillus are

Answer 25

Gram positive rods. Implicated in advanced dental caries

Question 26

Eubacterium are

Answer 26

Gram positive rods and filaments; difficult to grow in the laboratory; found in plaque

Question 27

Neisseria are

Answer 27

• Gram negative coccus; aerobic; early colonizer of tooth.

Question 28

Veillonella are

Answer 28

Gram negative coccus; anaerobic; utilizes lactic acid in plaque

Question 29

Treponema (spirochaetes)

Answer 29

strictly anaerobic; sub-gingival plaque; implicated in periodontal disease

Question 30

Fusobacterium are

Answer 30

– Gram-negative filament; Anaerobic; common in plaque; key “bridging” organism between early & late colonizers