Gram-negative bacteria

Question 1

what are the 4 groups of gram negative bacteria?

Answer 1

1. cocci
2. strict anaerobes (obligate)
3. facultative anaerobes
4. Curved rods

Question 2

what does strict anaerobe (obligate) mean?

Answer 2

restricted to a particular function or mode of life.

Obligate anaerobes are

• poisoned by oxygen
• avoid contact with oxygen in order to grow

Question 3

what does facultative anaerobe mean?

Answer 3

Not restricted to a particular function or mode of life

Facultative anaerobes can
- grow with or without oxygen because they have 2 different ways of metabolising (with & without O2)

Question 4

what are the 3 stages of periodontal disease and what bacteria are involved at each stage?

Answer 4

1. Plqaue accumulates around the neck of the tooth causing gingivitis (STREPTOCOCCUS)
2. Plaque grows down beneath the tooth & gum to form a pocket (ACTINOMYCES)
3. pocket deepens, gingivae recedes, bone is lost = periodontitis (PORPHYOMONAS GINGIVALIS & PREVOTELLA INTERMEDIA)

Question 5

Define a periodontal pathogen

Answer 5

An organism in high numbers causing periodontal disease where it would usually either not exist at all or would in much smaller numbers

Question 6

What does GNAB stand for?

Answer 6

Gram Negative Anaerobic Bacilli

Question 7

what are the generalised 2 types of GNABs?

Answer 7

• motile ( capable of movement )

- non - motile

Question 8

are motile or non-motile GNABs most dentally relevant?

Answer 8

non-motile

Question 9

name 4 non-motile GNABs

Answer 9

1. prophyromonas
2. prevotella
3. tamerella
4. fusobacterium

Question 10

how many micro-organisms are involved in perio disease?

Answer 10

10,000 - 100,000

Question 11

what does porphyromonas look like under a microscope?

Answer 11

dark purple pigmented

Question 12

what does porphyromonas need to exist and where does it get it from?

Answer 12

needs iron to live and gets it from haem

Question 13

what gives prophyromonas its dark purple pigmented colour?

Answer 13

the iron scavenging molecules on the surface

Question 14

where does porphyromonas obtain its energy from?

Answer 14

amino acids and peptides from the environment

Question 15

what does porphyromonas produce?

Answer 15

proteases

Question 16

what are proteases?

Answer 16

enzymes which break down proteins and peptides

Question 17

where is porphyromonas gingivalis found?

Answer 17

• ginigval sulcus

- periodontal pocket

Question 18

Porphyromonas gingivalis is a proven….?…. and has been shown to do ? in animal studies?

Answer 18

proven periodontopathogen and has ben proven to cause periodontitis and bone destruction in animal studies

Question 19

what does prevotella look like under a microscope?

Answer 19

dark purple pigmentation

Question 20

what type of GNAB is prevotella and what does it mean?

Answer 20

a saccharolytic GNAB

means sucrose is turned into acetic acid & succinic acid

Question 21

what is prevoltella found?

Answer 21

the gingival sulcus and periodontal pocket

Question 22

what type of prevotella is associated with periodontitis? how is it associated?

Answer 22

prevotella intermedia (numbers of the bacteria is associated with the severity of the periodontitis)

Question 23

what type of prevotella is associated with gingival health?

Answer 23

prevotella nigrescens (increased numbers found in health)

Question 24

what does tannerella forsythia look like under a microscope?

Answer 24

non - pigemented bacteria

Question 25

what type of GNAB is tannerella forsythia?

Answer 25

a sacchorolytic GNAB ( sucrose converted into acrtic acid and succinic acid )

Question 26

what is the relevance of tannerella forsythia on ginigval tissues?

Answer 26

It is a SIGNIFICANT organism in periodontitis but CANNOT show pathogenic activity in isolation

Question 27

what is a virulence factor?

Answer 27

factor required before an organism has the capacity to cause the host damage

Question 28

give some virulence factors for tannerella forsythia

Answer 28

- Fibronecitin/fibrinogen binding BSpA - apoptosis inducing factor - protease (enzyme that breaks down protein and peptides)

Question 29

what does tannerella forsythia have on its surface?

Answer 29

binding protein

Question 30

what is BSpA?

Answer 30

a surface binding protein

Question 31

what does BSpA do?

Answer 31

it induces the release of cytokines that are - BONE RESORBING - PRO-INFLAMMATORY so it basically induces the resorbtion of alveolar bone and induces inflammation

Question 32

what other bacteria does Tannerella forsythia interact with? what does this cause?

Answer 32

1. porphromonas gingivalis - to aid attachment to epithelial cells 2. fusobacterium

Question 33

what does fusobacterium look like under a microscope?

Answer 33

sprindle shaped (fusiform - tappering at both ends)

Question 34

how is fusobacterium usually arranged?

Answer 34

in pairs

Question 35

what properties of fusobacterium nucleatum make it pathogenic?

Answer 35

1. it is a BRIDGING organism - is created a sticky surface for other bacteria to bind to. 2. On disintegration the bacteria releases an endotoxin which is linked to periodontal disease

Question 36

fusobacterium can adhere to gram - or gram + bacteria?

Answer 36

both

Question 37

where is fusobacterium nucleatum found?

Answer 37

mainly in the human ginigval sulcus

Question 38

when combined to ??? fusobactrium nucleatum is assocaited with ???

Answer 38

when combined to TREPONEMA VINCENTII it is associated with NUG

Question 39

give an example of 2 spirochetes?

Answer 39

- treponema vincenitii | - treponema denticolla

Question 40

where are spirochetes found?

Answer 40

the base of the pocket

Question 41

what shape are spirochetes and how do they move?

Answer 41

spiral shaped with flagella that propels bacteria into a cell like cork screws