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

what are the primary colonisers of the oral environment

Answer 6

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

actinomyces
veillonella
gemella

Question 6

what are the primary colonisers of the oral environment

Answer 6

s. salivarius = early colonizer
s. oralis= ubiquitous
s. mitis= ubiquitous
s. sanguinis =colonise teeth
s. mutans and 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