microbiology part 2

Question 1

what is kochs posulates

Answer 1

Koch’s postulates (/ˈkɔːx/) are four criteria designed to establish a causative relationship between a microbe and a disease.

Question 2

is dental caries or gingivitis transferred between person to person

Answer 2

YES

Question 3

is the pathogen present in health in dental caries or ginigitivitis

Answer 3

yes/often

Question 4

does the pathogen satisfy kochs posulates in caries or gingivitis

Answer 4

no

Question 5

does pathogen produces virulence factors in caries and gingivitis

Answer 5

no

Question 6

how are conventional diseases transmitted

Answer 6

Sneezing, coughing through air and water droplets

Question 7

do conventional disease meet kochs posulates

Answer 7

yes

Question 8

what is dental disease described as

Answer 8

dysbiosis of the resident oral microbiota

Question 9

where to the cariogenic bacteria in the biofilm come from

Answer 9

two hypothesis

1. transmission eg from mother to baby
2. the harmful pathogens are present even in health but in such low numbers that its not clinically relevant

Question 10

how does dysbiosis occur

Answer 10

there must be some major ecological pressure - alters competitiveness

Question 11

what are the major ecological changes that that place for caries to occur

Answer 11

regular sugar attacks
reduced saliva
acidic pH

Question 12

when might people have reduced saliva flow

Answer 12

elderly people due to medication

or head and neck radiotherapy

Question 13

what are the key features of cariogenic bacteria

Answer 13

acid producing

tolerating acid

Question 14

what are some examples of cariogenic bacteria

Answer 14

MS
lactobacilli
bifidobacterium
scardovia

Question 15

what are the three plaque hypothesis

Answer 15

specific
non specific
ecological plaque hypothesis

Question 16

what is the specific plaque hypothesis

Answer 16

only one or two bacteria contribute to caries

Question 17

describe non specific hypothesis

Answer 17

many species have a role in caries production

Question 18

what is the ecological plaque hypothesis

Answer 18

that disease can be inhibited or prevented by controlling the ecological factors which can influence the shift of species growth in the oral microbiota( dysbiosis)
we can also promote symbiosis

Question 19

what is specificity in disease found in

Answer 19

microbial function

Question 20

describe the ecological plaque hypothesis

Answer 20

many species can contribute

Question 21

caries is preventable by

Answer 21

direct inhibition of causative organisms
maintenance of natural balance
interfering the ecological shifts to stop the shift in bacteria

Question 22

what shifts are involved with causing caries

Answer 22

increased sugar frequency —> more acid attacks
there more time at low pH
shift in the bacterial load
therefore health shifts to caries

Question 23

what are the forms of sucrose that are found in the

Answer 23

sticky slime( extracellular polysaccharides)
food reserves made from XS sugar( intracellular polysaccharides) 
fermentation process-lactic acid or other acids which acidifies the pH

Question 24

what are the bacteria associated with gum disease - in the mixed culture

Answer 24

F nucleatum
P gingivalis
P nigrescens

Question 25

what bacteria are associated with health - in the mixed culture

Answer 25

``` S gordonii S oralis A naeslundii N subflava V dispar ```

Question 26

what bacteria are associated with disease - in the mixed culture

Answer 26

S mutans | L caesi

Question 27

what could we alter when carrying out the experiment

Answer 27

the sugar content | and the pH

Question 28

describe the experiment which models the oral biota

Answer 28

beneficial bacteria growing on agar plate pH of 7 strep mutans L caesi were both only at 1% in the population and non competitive

Question 29

what were the results when glucose was pulsed in and pH was constant

Answer 29

nothing happened as the beneficial bacteria are growing and are more competitive than the disease bacteria

Question 30

what were the results when glucose was pulsed in and pH was not constant

Answer 30

low pH | healthy species was reduced and the cariogenic bacteria increased to more than 50%

Question 31

what is the relationship between pH and % of cariogenic bacteria

Answer 31

inverse relationship

Question 32

what happens the lower the pH of the mouth

Answer 32

the more competitive the bacteria and greater % of cariogenic bacteria

Question 33

what happens when fluoride is added

Answer 33

it slows down the acid production

Question 34

what was the % of strep mutans when fluoride wasn't present in the study

Answer 34

23%

Question 35

what was the % of strep mutans when fluoride was present in the study

Answer 35

less than 3%

Question 36

what was the pH in the study when fluoride wasnt present

Answer 36

4.55

Question 37

what was the pH in the study when fluoride was present

Answer 37

5.55

Question 38

what are the approaches for controlling dental caries

Answer 38

``` plaque control-brushing floss fluoride sugar substitutes antimicrobial and anti plaque modify the microbiota vaccination passive immunisation ```

Question 39

what does fluoride do

Answer 39

it can enter the cell and inhibit glycolysis | stops the pH falling that much so disease causing bacteria cannot grow

Question 40

give examples of sugar substitutes

Answer 40

bulking agents- sorbitol and xylitol | intense sweeteners - saccharin and aspartame

Question 41

how do we control dental caries

Answer 41

``` bulking agents intense sweeteners weakly metabolised in acid stimulate saliva flow weak antimicrobial activity ```

Question 42

what is the gold standard of antimicrobial, anti MS, anti plaque mouthwash

Answer 42

chlorhexidine- only used for a short period eg 7 days | in the mouth for 1-2 mins

Question 43

why is triclosan phased out

Answer 43

found in the environment eg in polar bear cells

Question 44

what is the pathway of fluroide ions

Answer 44

forms HF and shoots across the extracellular membrane. once enters the cell splits into H and F and the fluoride inhibits glycolysis enzyme pathway

Question 45

what does streptococcus dentisani do

Answer 45

arginolytic

Question 46

what does streptococcus A12 do

Answer 46

bacteriocin inhibits MS

Question 47

how do we modify the microbiota

Answer 47

replacement therapy genetically modified strep mutans introduced to kids and removed the enzyme that leads to lactic acid production and inhibits natural strep mutans

Question 48

what are prebiotics

Answer 48

molecules that stimulate the growth of beneficial bacteria eg arginine in toothpaste

Question 49

what is the full immune response found in the mouth

Answer 49

SIgA, IgG,neutrophils and complement

Question 50

what are vaccines based on

Answer 50

whole cell glucosyltransferases cell wall associated proteins

Question 51

examples of passive immunity

Answer 51

coat surfaces with antibodies or synthetic body fragments

Question 52

advantage of passive immunity

Answer 52

safe acceptable non invasive no cross reaction with human tissues no side effects