Periodontal Pathogens Flashcards
What hypothesis considers all plaque bacteria bad and states that any accumulation at or below the gingival margin causes inflammation?
Non-specific plaque hypothesis
Because not everyone with plaque has periodontal disease, what hypothesis states that specific organisms in dental plaque are the etiological agents?
Specific plaque hypothesis
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).
True.
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?
Ecological plaque hypothesis
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?
oral dysbiosis
T/F. The strain of the virulent periodontal pathogen may be more important than the species in disease.
True. P.gingivalis with type I and V fimA genotypes -healthy, type II and IV in disease
Periodontal pathogens must express ___ factors and must be in the right location in the site.
virulence
The local environment can be colonized by beneficial species that ___ levels of pathogens and ___ pathogens.
dilute; inhibit
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.
subgingival; iron; fimA
What are four pathogenic mechanisms that bacteria colonize?
- adhesins on bacteria bind to host receptors
- coaggregation
- nutrient utilization
- competitive inhibition
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.
invade; desquamation
How do pathogenic bacteria prevent antibodies from binding?
IgG and IgA proteases
mimic host antigens
Pathogenic bacteria evade phagocytic cells by producing ___ and causing non-lethal suppression of ___ cells.
leukotoxin; immune
What three pathogens did the world workshop in 1996 designate as periodontal pathogens?
P.gingivalis
A.actinomycetemcomitans
T.forsythia
According to the subgingival microbial complexes, where can those pathogens that consistently cause disease be found?
in the red complex
What does AA stand for?
Actinobacillus actinomycetemcomitans
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.
negative; saccharolytic; capnophilic; round; star
What are the virulence factors for AA?
TLC Female Ensemble: Tissue invasive- epithelial and endothelial cells Leukotoxin Collagenase Fibroblast inhibiting factor Endotoxin
What commensal bacteria does AA inhibit the growth of?
Streptococcus sanguis
What evidence is there against AA being a pathogen?
- Not seen in all cases of aggressive periodontitis
- 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.
AA with ___bp deletion is 23X more likely to be disease-associated than AA with full length promoter region.
530
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.
5; polysaccharides; surface antigens; one; stable
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
b; PMNs; a
AA requires ___ and ___ approach to treatment. What specifically is done?
mechanical; chemotherapeutic
Amoxicillin 500mg + Metronidazole 250mg effective in reducing bacterial load
Surgical approach required to eliminate tissue reservoirs because AA in tissue invasive
___ gingivalis is a gram-negative, ___, non-motile bacteria that has ___ rods and is a ___ pigmented Bacteriodes.
Porphyromonas; anaerobic; asacharolytic (does not break down sugars); black
What virulence factors are produced by P. gingivalis?
collagenase, proteases, hemolysins, endotoxin, fatty acids, NH3, H2S and indole
What type of proteinases are important in protein degradation and in the maturation of cell surface proteins such as fimA fimbrillin?
cysteine proteinases (ARG-gingipain and LYS-gingipain)
Tannerela forsythia is a gram-negative, ___, ___-shaped highly ___ rod that requires _-___ ___ (NAM).
anaerobic; spindle; pleomorphic; N-acetylmuramic acid
Tannerella forsythia co-cultivates with _. ___ and has a ___ __-layer on its cell surface that mediates ___ and ___.
F. nucleatum; serrated S; adhesion; hemagglutination
What is the name of the Spriochete pathogen?
Treponema denticola
Treponema denticola is a gram-negative, ___, ___-shaped highly ___ microorganism that was 1st identified in ___. It contains several different species that are hard to distinguish.
anaerobic; helical; ANUG (acute necrotizing ulcerative gingivitis)
Provotella intermedia/nigrescens is a gram-negative, ___, short ___-ended rod seen as ___ pigmented Bacteriodes. It has luxuriant growth in ___. It is elevated in ___.
anaerobic; round; black; naphthoquinone; NUG
Why is it believed that Prevotella intermedia /nigrescens is associated with puberty/pregnancy gingivitis?
It grow well in naphtoquinone and there are high levels of steroids in the gingival surfaces of these patients.
Fusobacterium nucleatum is a gram-negative, ___, ___-shaped rod that serves as an ___ colonizer in plaque because it acts a ___ organism.
anaerobic; spindle; early; bridging
Which pathogen is the most common isolate cultured from subgingival microbiota in health and disease?
Fusobacterium nucleatum
Fusobacterium nucleatum can induce cell death in ___. What is released from these cells?
leukocytes
cytokines, elastase, and oxygen radicals
