M11- Gram- negative bacteria part 2

Question 1

Name 3 non-motile gram negative anaerobic bacilli.

Answer 1

• tannerella
• fusobacterium
• leptotrichia

Question 2

what is tannerella forsythia?

Answer 2

Saccharolytic , non-pigmented bacteria

pits the surface of blood agar

Question 3

what is tannerella forsythia associated with?

Answer 3

periodontitis

chronic periodonititis and increased recovery with depth

Question 4

Can tannerella forsythia demonstrate pathogenic activity in isolation?

Answer 4

NO

Question 5

what does tannerella fit into?

Answer 5

RED complex

Question 6

Name some virulence factors of tannerella forsythia.

Answer 6

• fibronectin/fibrinogen binding BspA

- apoptosis inducing factor -protease (take out compliment)

Question 7

What does BspA do?

Answer 7

– Adhesion
– Invasion
– Induces release of bone reabsorbing pro-inflammatory cytokines
– Induces chemokines (recruit neutrophils, inflammation, tissue destruction)

Question 8

why is tannerella forsythia pathogenicity limited (polymicrobial)?

Answer 8

– Murine skin abscess model & wound chamber model does not cause
disease
– Gnotobiotic rats does not colonize efficiently or induce alveolar bone loss

Question 9

what interactions does tannerella forsythia make?

Answer 9

– P. gingivalis enhances attachment to epithelial cells

– Forms mixed films with Fusobacterium

Question 10

What are features of fusobacterium nucleatum?

Answer 10

• Diversification of Plaque
• Periodontal Disease
• NG -necrotising gingivitis
• Still Births (gets in oral cavity and cross the placenta - so effects systemic health
• Colorectal Cancer

Question 11

what type of bacteria is fusobacterium?

Answer 11

gram negative spindle shaped (fusiform) bacteria (often arranged in pairs)

Question 12

what can fusobacterium nucleatum adhere?

Answer 12

Gm +ve and Gm -ve bacteria

Question 13

what is fusobacterium nucleate FadA virulence factor involved in?

Answer 13

extra-oral infections

Question 14

what does fusobacterium bind to?

Answer 14

epithelial cells, seen to enter fibroblasts in vitro

Question 15

what is fusobacterium nucleatum associated with?

Answer 15

other microorganisms in disease

Question 16

what is F. nucleatum and Treponema vincentii spirochaete normally associated with?

Answer 16

• necrotizing periodontal diseases

- acute necrotizing ulcerative gingivitis

Question 17

what is the combination of F. nucleatum and treponema vincentii spirochaete?

Answer 17

fusospirochaetal infection

Question 18

what is Vincent’s angina?

Answer 18

Old ANUG name for infection of

tongue/pharynx & mouth

Question 19

what is cancrum oris or NOMA?

Answer 19

– AUG causing massive tissue destruction

– Linked to immunosuppression

Question 20

who does necrotising gingivitis affect normally?

Answer 20

immunocompromised people

Question 21

what are features of necrotising gingivitis?

Answer 21

• Young adults (mainly)
• Cigarette smokers & minor respiratory infections
• Ulcers spread along gingival margins
• Gingival soreness & bleeding
• Foul breath
• No swollen lymph nodes, fever or systemic symptoms

Question 22

how does fusobacteria cause NG?

Answer 22

• Induce protein kinases associated with cell migration, proliferation & cell survival
  – Stimulates collagenase 3 expression
  – Secretes serine proteases
  – Immune suppression via inducing apoptotic cell death in peripheral blood cells i.e. mononuclear & polymorphonuclear

Question 23

what to remember about fusobacteria?

Answer 23

• sticks to other organisms
• mutilpe interactions (peridontal disease - stimulation of immune system)
• carry other cells into tissues
• key roles in cancer and still birth

Question 24

what is Leptotrichia?

Answer 24

• gram negative anaerobic bacilli

- found in pairs or long filaments

Question 25

what is the major fermentation product of leptotrichia?

Answer 25

lactic acid

Question 26

what is the best described species of leptotrichia?

Answer 26

Leptotrichia buccalis

Question 27

Describe Leptotrichia buccalis.

Answer 27

– present in dental plaque -preferentially isolated from plaque overlying caries – Possess galactosyl-binding lectins – Extra-oral infections in seriously ill patients

Question 28

Describe gram -ve facultative anaerobes.

Answer 28

``` • Prefer Oxygen • Often capnophilic (5 - 10% CO2) • important oral genera include: -Haemophilus -Eikenella -Aggregatibacter -Capnocytophaga ```

Question 29

what is haemophilus?

Answer 29

• Gram -ve small bacilli (Parvobacteria) – frequently isolated from mouth and dental plaque – Haemophili colonise the mouth in the first few days after birth

Question 30

what is the most common haemolphilus species in dental plaque?

Answer 30

haemophilus segnis (supragingivial plaque)

Question 31

Is haemophilus segnis regarded as pathogenic?

Answer 31

no

Question 32

what species works on its own?

Answer 32

Aggregatibacter

Question 33

what is aggregatibacter?

Answer 33

* Gram -ve, capnophilic (5-10%), cocco-bacillus – often found in association with Actinomyces * Periodontopathogen (Localised Juvenile Periodontitis)

Question 34

Name some virulence factors of aggregatibacter.

Answer 34

Leukotoxin (takes out white blood cells), collegenase, IgG proteases, surface proteins

Question 35

Describe juvenile periodontitis.

Answer 35

* Puberty, more common in Girls * Clusters in families * West African & Asian (slightly more common) * Localised J P (first permanent molars & incisors) * Generalised J P (aggressive)

Question 36

what does A. actinomycetemcomitans cause?

Answer 36

* Rapid destructive periodontitis | * Juvenile periodontitis (11-15)

Question 37

what is eikenella?

Answer 37

• Gram -ve asaccharolytic small bacillus (coccobacilli) – that pits or corrodes agar

Question 38

what does eikenella corrodes colonise?

Answer 38

the oral cavity and intestine | -subgingival plaque

Question 39

what can eikenella cause?

Answer 39

Can produce periodontitis and alveolar bone loss when introduced into rats – Increased numbers in gingivitis

Question 40

what is clenched first injury?

Answer 40

* 21 year old cut hand * 12 hours after hitting an opponent in the mouth * Rapid onset/redness (erythema)

Question 41

what is capnocytophaga?

Answer 41

Gram -ve, fusiform, CO2-dependent, | Parvobacteria

Question 42

Describe curved gram -ve bacilli.

Answer 42

Many curved/spiral Gram -ve bacteria are found in the mouth. These are usually anaerobic with polar flagellae e.g. • Campylobacter rectus – plaque and periodontal pockets

Question 43

what is the core knowledge of gram negative key species?

Answer 43

``` • Tannerella forsythia – Red complex, Perio-bone loss, BspA • Fusobacterium nucleatum – Bridging organism, perio, extra-oral, still births, FadA • Aggregatibacter actinomycetemcomitans – Perio, juvenile perio, leukotoxin,Amoxycillin & Metronidazole • Eikenella corrodens – Perio & clenched fist injuries ```

Question 44

what makes up the RED complex?

Answer 44

– Tannerella forsythia – Porphyromonas gingivalis – Treponema denticola

Question 45

what is the orange complex?

Answer 45

– Prevotella intermedia – Prevotella nigrescens – Fusobacterium nucleatum