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Flashcards in GRAM -VE Deck (46):
1

Name 3 gram negative cocci

1. Neisseria
2. Moraxella
3. Veillonella

2

What type of bacteria is Neisseria?

Gram-negative cocci that is facultative aerobic

3

Appearance of Neisseria on gram stain?

Pink;
Cocci - found in pairs, tetrads, short chains & clusters

4

List 2 species of Neisseria that are pathogens

1. Neisseria gonorrhoeae
2. Neisseria meningitidis

5

List 2 species of Neisseria that can be found in the oral cavity

1. Neisseria subflava
2. Neisseria sicca

6

Are the Neisseria species early or late colonizers of tooth?

Early

7

Name a similarity and a difference between Neisseria subflava and Neisseria sicca

S: N. subflava and N. sicca are saccharolytics and polysaccharide producing bacteria found in the mouth
D: N. subflava produces a yellow-green pigment but N. sicca does not produce pigment.

8

State a difference between Neisseria and Moraxella

Neisseria is saccharolytic (i.e. produces polysaccharide) but Moraxella is asaccharolytic (i.e. does not produce polysaccharide)

9

Name a species of Moraxella

Moraxella catarrhalis

10

What do most strains of Moraxella produce? Why is that a danger?

Most strains produce B-lactamase --> complicates antibiotic therapy

11

Where can Moraxella catarrhalis be found?

Commensal of the mouth and upper respiratory tract

12

What is Moraxella catarrhalis a significant pathogen of?

Meningitis, endocarditis, otitis media, maxillary sinusitis

13

Similarity between Moraxella and Veillonella

Both are asaccharolytics (both do not ferment carbohydrates)

14

Where can Veillonella be found?

Mouth and dental plaque

15

Function of Veillonella

Catabolises lactic acid to weaker organic acids (acetate and propionate); hence raising pH of the oral cavity

16

Name the most common species of Veillonella

Veillonella parvula

17

Where can veillonella parvula be found?

Oral cavity and intestines

18

Name 3 species of Veillonella

1. Veillonella Parvula
2. Veillonella Dispar
3. Veillonella Atypica

19

Define GNAB

GNAB = Gram negative anaerobic bacteria - They are a large proportion of oral bacteria found especially in the gingival sulcus and periodontal pocket that is difficult and fastidious to study.

20

Name 3 motile GNAB

1. Selenomonas
2. Centipeda
3. Helicobacteria

21

Name 6 non-motile GNAB

1. Bacteriodes
2. Porphyromonas
3. Prevotella
4. Tannerella
5. Fusobacterium
6. Leptotrichia

22

What are selenomonas associated with?

Periodontitis / Periodontal disease

23

Describe the appearance of Selenomonas

Cresent (moon-shaped) with many flagellae

24

Name 3 species of Selenomonas

1. Selenomonas Sputigena
2. Selenomonas Flueggei
3. Selenomonas Noxia

25

Name a species of Centipeda

Centipeda Periodontii

26

Describe the appearance of Centipeda

flagellae arising from all around the cell

27

Name a species of Helicobacter

Helicobacter pylori

28

What does helicobacter pylori cause?

gastritis, gastric cancer, peptic ulcers

29

Describe the appearance of bacteroides on a CBA

Produces a dark pigment

30

Name a species of bacteroides. Where can it be found?

Bacteroides fragilis; found in mouth and GI tract (esp in the colon)

31

Where does the dark appearance of certain species of bacteria on CBA come from?

Dark appearance comes from the iron scavenging molecules on the surface which require an external heme as the iron source

32

Where can porphyromonas be found?

Exclusively in gingival sulcus and periodontal pocket

33

Name a species of Porphyromonas and the associated disease

Porphyromonas gingivalis; frequently associated with periodontitis

34

Name 3 black pigmented bacteria

1. Porphyromonas gingivalis
2. Prevotella intermedia
3. Prevotella nigrescens

35

Are porphyromonas saccharolytic or asaccharolytic?

Asaccharolytic

36

What is the source of energy for Porphyromonas?

Environmental amino acids and peptides - Porphyromonas produce proteases to access them. They degrade serum albumin, immunoglobulins, haemoglobins and host tissue proteins

37

Name 3 species of Prevotella

1. Prevotella Intermedia
2. Prevotella Nigrescens
3. Prevotella Dentalis

38

Are Prevotellas saccharolytic or asaccharolytic?

Saccharolytic - Breaks down sucrose into acetic acid and succinic acid

39

Which Prevotella species correlates with periodontitis severity?

Prevotella intermedia

40

Which Prevotella species is present in high numbers at healthy sites?

Prevotella Nigrescens

41

List the bacteria involved in gum disease in sequence

1. Streptococcus
2. Actinomyces
3. Porphyromonas gingivalis & Prevotella intermedia

42

How do the conditions for bacterial growth below the gingival margin differ from the tooth surface?

1. Conditions are more anaerobic (requires carbon dioxide)
2. Nutrients come from the gingival tissues rather than food and saliva (gingival crevicular fluid)

43

Describe the structure of Spirochaetes

Spirochaetes are helical shaped bacteria with a central protoplasmic cell and 3-5 axial filaments or flagellae within the outer cell envelope

44

What disease does a fuso-spirochaetal complex cause?

ANUG (Acute Necrotizing Ulcerative Gingivitis)

45

Bacteria involved in Acute Necrotising Ulcerative Gingivitis

Fusobacterium nucleatum
Treponema vincentii

46

Periopathogens

Treponema Denticola
Porphyromonas Gingivalis
Aggregatibacter Actinomycetemcomitans