Periodontal Pathogens

Question 1

What hypothesis considers all plaque bacteria bad and states that any accumulation at or below the gingival margin causes inflammation?

Answer 1

Non-specific plaque hypothesis

Question 2

Because not everyone with plaque has periodontal disease, what hypothesis states that specific organisms in dental plaque are the etiological agents?

Answer 2

Specific plaque hypothesis

Question 3

T/F. The specific plaque hypothesis believes that microbial composition of disease sites is different than healthy sites and that local debridement and systemic antibiotics could control LAP (localized aggressive periodontitis).

Answer 3

True.

Question 4

Which hypothesis states that everyone has high healthy associated bacteria and low levels of disease associated bacteria and if the ratio changes, then there is an increase in inflammation?

Answer 4

Ecological plaque hypothesis

Question 5

What hypothesis states that a group of organisms live happily together but when their environment changes (increased inflammation, decreased oxygen) the different environment supports a new set of organisms colonize and can cause disease?

Answer 5

oral dysbiosis

Question 6

T/F. The strain of the virulent periodontal pathogen may be more important than the species in disease.

Answer 6

True. P.gingivalis with type I and V fimA genotypes -healthy, type II and IV in disease

Question 7

Periodontal pathogens must express ___ factors and must be in the right location in the site.

Answer 7

virulence

Question 8

The local environment can be colonized by beneficial species that ___ levels of pathogens and ___ pathogens.

Answer 8

dilute; inhibit

Question 9

An example of the effect of the local ‘regulon’ in the ___ environment is when ___ increases outer membrane protein expression in P. gingivalis or when S. cristatus inhibits ___ expression.

Answer 9

subgingival; iron; fimA

Question 10

What are four pathogenic mechanisms that bacteria colonize?

Answer 10

1. adhesins on bacteria bind to host receptors
2. coaggregation
3. nutrient utilization
4. competitive inhibition

Question 11

In an effort to avoid being loss when the epithelium sheds its surface, pathogens ___ the epithelium and bind to underlying cells. This is known as ___ of epithelium.

Answer 11

invade; desquamation

Question 12

How do pathogenic bacteria prevent antibodies from binding?

Answer 12

IgG and IgA proteases

mimic host antigens

Question 13

Pathogenic bacteria evade phagocytic cells by producing ___ and causing non-lethal suppression of ___ cells.

Answer 13

leukotoxin; immune

Question 14

What three pathogens did the world workshop in 1996 designate as periodontal pathogens?

Answer 14

P.gingivalis
A.actinomycetemcomitans
T.forsythia

Question 15

According to the subgingival microbial complexes, where can those pathogens that consistently cause disease be found?

Answer 15

in the red complex

Question 16

What does AA stand for?

Answer 16

Actinobacillus actinomycetemcomitans

Question 17

AA is a gram ___ non-motile pathogen that breaks down sugars (___) and lives in a CO2 environment (___) with ___-ended rods and a characteristic ___-shaped colonies when grown on blood agar.

Answer 17

negative; saccharolytic; capnophilic; round; star

Question 18

What are the virulence factors for AA?

Answer 18

TLC Female Ensemble:
Tissue invasive- epithelial and endothelial cells
Leukotoxin 
Collagenase
Fibroblast inhibiting factor
Endotoxin

Question 19

What commensal bacteria does AA inhibit the growth of?

Answer 19

Streptococcus sanguis

Question 20

What evidence is there against AA being a pathogen?

Answer 20

1. Not seen in all cases of aggressive periodontitis
2. Seen in periodontally healthy subjects
   DiRienzo & McCay 1994 - genetic analysis of the 3. -leukotoxin gene
   -13 distinct genetic cluster groups identified from clinical samples
   -Cluster II seen in severe disease cases.
   -Cluster XII / XIV associated to health.

Question 21

AA with ___bp deletion is 23X more likely to be disease-associated than AA with full length promoter region.

Answer 21

530

Question 22

AA has ___ serotypes based on the ___ on its surface. The serotype specific ___ ___ (SPA) are dominant antigens. Patients are infected with ___ serotype. Each serotype is ___ over time.

Answer 22

5; polysaccharides; surface antigens; one; stable

Question 23

Serotype ___ most commonly associated with localized aggressive periodontitis in USA and it has a role in resistance to phagocytosis and killing by ___. Serotype ___ health-associated in Finland, disease-associated in Japan

Answer 23

b; PMNs; a

Question 24

AA requires ___ and ___ approach to treatment. What specifically is done?

Answer 24

mechanical; chemotherapeutic

Amoxicillin 500mg + Metronidazole 250mg effective in reducing bacterial load
Surgical approach required to eliminate tissue reservoirs because AA in tissue invasive

Question 25

___ gingivalis is a gram-negative, ___, non-motile bacteria that has ___ rods and is a ___ pigmented Bacteriodes.

Answer 25

Porphyromonas; anaerobic; asacharolytic (does not break down sugars); black

Question 26

What virulence factors are produced by P. gingivalis?

Answer 26

collagenase, proteases, hemolysins, endotoxin, fatty acids, NH3, H2S and indole

Question 27

What type of proteinases are important in protein degradation and in the maturation of cell surface proteins such as fimA fimbrillin?

Answer 27

cysteine proteinases (ARG-gingipain and LYS-gingipain)

Question 28

Tannerela forsythia is a gram-negative, ___, ___-shaped highly ___ rod that requires _-___ ___ (NAM).

Answer 28

anaerobic; spindle; pleomorphic; N-acetylmuramic acid

Question 29

Tannerella forsythia co-cultivates with _. ___ and has a ___ __-layer on its cell surface that mediates ___ and ___.

Answer 29

F. nucleatum; serrated S; adhesion; hemagglutination

Question 30

What is the name of the Spriochete pathogen?

Answer 30

Treponema denticola

Question 31

Treponema denticola is a gram-negative, ___, ___-shaped highly ___ microorganism that was 1st identified in ___. It contains several different species that are hard to distinguish.

Answer 31

anaerobic; helical; ANUG (acute necrotizing ulcerative gingivitis)

Question 32

Provotella intermedia/nigrescens is a gram-negative, ___, short ___-ended rod seen as ___ pigmented Bacteriodes. It has luxuriant growth in ___. It is elevated in ___.

Answer 32

anaerobic; round; black; naphthoquinone; NUG

Question 33

Why is it believed that Prevotella intermedia /nigrescens is associated with puberty/pregnancy gingivitis?

Answer 33

It grow well in naphtoquinone and there are high levels of steroids in the gingival surfaces of these patients.

Question 34

Fusobacterium nucleatum is a gram-negative, ___, ___-shaped rod that serves as an ___ colonizer in plaque because it acts a ___ organism.

Answer 34

anaerobic; spindle; early; bridging

Question 35

Which pathogen is the most common isolate cultured from subgingival microbiota in health and disease?

Answer 35

Fusobacterium nucleatum

Question 36

Fusobacterium nucleatum can induce cell death in ___. What is released from these cells?

Answer 36

leukocytes

cytokines, elastase, and oxygen radicals