Periodontal Pathogens Flashcards
What is the “non-specific plaque hypothesis”?
Direct correlation between the amount of plaque and the amount of inflammation because all bacteria are considered bad. By this hypothesis, plaque control is important in perio treatment
What is the “specific plaque hypothesis”?
There is not a direct 1:1 correlation between amount of plaque and inflammation because only certain bacteria are considered bad. Disease sites differ from healthful sites because specific organisms are the etiological agents.
What is the “ecological plaque hypothesis”?
How the body reacts to bacteria will push the environment and ecology toward specific organisms. For example, plaque accumulation causes inflammation which will lead to an environmental change (more GCF flow) and then an ecological shift will occur that better supports anaerobic and gram negative organisms.
What is the theory of Oral Dysbiosis?
Bacteria may have more than one role in manifestation of disease; the capability of bacteria causing damage directly depends on the presence of other cells for nutrients or modulation.
What are the three prerequisites for disease initiation and progression?
- The virulent periodontal pathogen (exhibiting virulence)
- The local environment
- Host susceptibility
What is the surface protein in P.gingivalis that distinguishes healthy vs disease types?
fimA
I and V = healthy
II and IV = perio
What is “niche saturation”?
colonization by beneficial species of bacteria which dilutes levels of pathogenic species
______ can increase outer membranes protein (OMP) expression in P.gingivalis and lead to _______.
Iron
Inflammation
What are four methods of pathogenic colonization?
- Adhesins on bacteria (bind to host receptors)
- Coaggregation
- Nutrient Utilization (symbiosis)
- Competitive Inhibition (hydrogen peroxide production)
How can a pathogen overcome the hosts desquamation of epithelium (defense mechanism)?
By invading and binding to underlying cells
How can a pathogen overcome antibodies that prevent binding?
By mimicking host antigens
How can a pathogen evade phagocytic cells of the host?
Through non-lethal suppression of immune cells and release of toxins (leukotoxin by A.a)
Which three periodontal pathogens were designated in 1996 as relating to disease?
P. gingivalis
A. actinomycetemcomitans
T. forsythia
In the color-coding system for subgingival microbial complexes: how are red, orange, and yellow complexes distinguished?
Red-Complex: bacteria consistently related to disease
Orange: probably pathogenic bacteria
Yellow: health compatible bacteria but could be pathogenic
Which three bacteria are strongly associated with periodontal disease?
Actinobacillus actinomycetemcomitan (A.a) Porphyromonas gingivalis (P.g) Bacteroides forsythus (B.f)
T. denticola and F.nucleatum are considered to be periodontal pathogens with _______ evidence of pathogenicity.
moderate
True or False: A.a is non-motile.
True
Is A.a gram positive or gram negative?
negative
What is characteristic about A.a colonies?
A.a forms star shaped colonies
A.a is ________, meaning that it metabolizes sugars for energy.
saccharolytic
What are the five considerations in determining pathogenicity of an organism?
- Association
- Elimination
- Host Response
- Virulence Factors
- Animal Studies
Describe evidence for A.a pathogenicity in regard to Koch’s five postulates.
- Association: A.a detected in active sites and high numbers are associated with aggressive perio
- Elimination: elimination results in successful therapy
- Host Response: high level antibody response
- Virulence Factors: Tissue invasive collagenase, leukotoxin, endotoxin, Fibroblast inhibiting factor
- Animal Study: induces disease in animal models
What are some arguments against A.a as an etiological pathogen in perio?
Not seen in all cases
Seen in healthy cases
Specific strains of A.a could be associated with health
There are ______ serotypes of A.a that are based on ______ on the surface of the organism.
five
polysaccharides
Which serotype of A.a is most commonly associated with disease?
B
Treatment for removal of A.a requires a _______ AND ______ approach.
mechanical chemotherapeutic (reduce bacterial load)
Which of the following is not a virulence factor of A.a: leukotoxin, collagenase, lipoteichoic acid, lipopolysaccharide.
Lipoteichoic acid (teichoic acid is associated with gram +)
Which has higher levels of murein, gram negative or gram positive?
Gram positive
Which has an outer membrane, gram positive or gram negative?
Gram negative
Which has a thick, multilayer of peptidoglycan, gram positive or negative?
Gram positive
Which contains teichoic acid in its cell wall, gram positive or gram negative?
Gram positive
P. gingivalis is gram ______.
negative
A.a has ______ and _____ which induce apoptosis.
leukotoxin
LPS
P. gingivalis is non-motile and forms characteristic ______ bacteroides in culture.
Black Pigment
True or False: P. gingivalis grows on iron (blood) and forms black pigmented colonies.
True
__________ in P.gingivalis are important for protein degradation and maturation of cell surface proteins such as fimA.
Cysteine proteinases (ARG-gingipain, LYS-gingipain)
What are the two important cysteine proteinases in P.gingivalis?
ARG-gingipain
LYS-gingipain
A.a is saccharolytic; P.gingivalis is _______.
asaccharolytic
Which virulence factors does P.g produce?
collagenase protease hemolysin endotoxin NH3 and H2S indole
True or False: P.g is a primary colonizer.
False
The presence of P.g indicates an increased risk for ______.
attachment loss (strong association=evidence as pathogen)
Even in a diseased state, P.g does not exist in high numbers in which oral environment?
the subgingival community= only 0.3%
Fimbriae, hemagluttinins, OMPs, and vesicals are involved in ______ and ______ of P.gingivalis.
colonization and attachment
Proteases, LPS, and antiphagocytic products are P.gingivalis characteristics involved in ________.
evading host responses
Which two proteins are involved in P.gingivalis multiplication?
proteinases and hemolysins
_____ and _____ gingipains (proteinases) are involved in host damage by P.gingivalis.
Arg-
Lys-
Tannerella forsythia is a gram ______ pathogen that requires _____ for growth.
negative
N-acetymuramic acid (NAM)
Which pathogen does T. forsythia co-cultivate with?
F. nucleatum
Which virulence factor on the surface of T. forsythia will mediate adhesion and allow hemagglutination?
its serrated “S-layer”
T. forsythia and T. denticola are part of the ______ complex.
Red
Which perio bacteria in the red complex will exist as spirochetes?
T. denticola
T. denticola is gram _____.
Negative
True or False: Like the other red complex organisms, T. denticola is non-motile.
False- T.d is HIGHLY MOTILE
What is T. denticola’s “claim to fame”?
It was first identified in Acute Necrotizing Ulcerative Gingivalis (ANUG)
In addition to P.gingivalis, _______ forms black pimented baceriodes.
Prevotella nigrescens/ P. intermedia
P.nigrescens is gram _____ and grows extremely well in high levels of ______.
negative
naphthoquinone and estrogen
Which bacteria is associated with puberty and pregnancy-related gingivitis?
P. nigrescens (estrogen and naphthoquinone)
Sites with P.nigrescens (P.intermedia) show persistent ______.
BOP
Fusobacterium nucleatum is gram ______ bridging organism.
negative
Which bacterial species is the most common isolate cultured from subgingival microbiota in both health and disease?
F. nucleatum
F. nucleatum releases _______, elastase, and ______ from leukocytes.
cytokines
oxygen radicals
Which organism is found MOST often in both remission and progression of adult periodontitis?
F. nucleatum (but its still higher in disease than health)
True or False: There are several gram positive species of bacteria that are associated with disease.
True
True or False: There are several gram negative species of bacteria that are associate with health.
True
True or False: Niche saturation helps to maintain a healthy biofilm.
True
Are chairside microbial tests good indicators of disease?
No, because the presence of particular bacteria does not give conclusive evidence for disease state
_______ concept: promotes control of diseases before all other treatments.
Cross-infection
Name a small, anaerobic, gram-POSITIVE bacterial species.
P.micros
