Cheatography
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Oral Ecosystem:
- Specific microbial species demonstrating tropism for specific tissues |
- Microbial interaction with each other as well as with the oral environment |
Formation of an Ecosystem:
Indigenous Microbiota: |
Most numerous, Compatible with host |
Supplemental Microbiota: |
Potentially pathogenic, Can become invasive |
Transient Microbiota: |
Don't have mechanisms for persisting in the host |
Oral Ecosystems:
Buccal epithelium: |
Gram-positive cocci |
Lingual epithelium: |
Gram-positive filaments |
Supragingival tooth surface: |
Faculative G+ rods and cocci |
Subgingival tooth surface: |
Anaerobic G- rods and cocci |
Microenvironments:
Supragingival:
-Bathed in saliva
-Faculatively anaerobic
-Increased mechanical disruption (swallowing, abrasion) |
Subgingival:
-Bathed in crevicular fluid
-Anaerobic
-Reduced mechanical disruption (anatomy of gingival sulcus)
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Environmental Factors:
Oxygen tension: |
pO2, partial pressure of oxygen, mmHg |
Redox Potential: |
Eh, tendency to acquire electrons and thus be reduced, mV |
pH: |
controlled by exogenous materials carbohydrate fermentation buffering capacity of plaque and saliva |
Temperature: |
variations |
Availability of Nutrients: |
carbohydrates, amino acids (salivary glycoproteins), hemin (plasma) |
Host Fluids:
Antagonists |
Synergistic: |
Nutrients from saliva and GCF |
sIgA: |
Interferes with colonisation |
Glycoproteins: |
Aggregation and removal |
Lactoperoxidase: |
Inactivation of glycolytic enzymes - death |
Lactoferrin: |
Binds iron limiting bacterial growth |
Lysozyme: |
Degrades bacterial peptidoglycan |
Host Susceptibility:
- Geographic location
- Ethnicity and culture
- Diet
- Health and social status
Microbial Factors:
Adherence:
- Contact: proximity
- Dose: quantity of bacteria
- Frequency of exposure (eg newborns)
- Absorption: initial reversible association with oral tissues |
Retention:
- Ability to accumulate at entry site
- Adaption
- Resist host defenses
- Competition from other species
- Changing environments
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Co-Aggregation:
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Different species, or different strains of a single species, have distinct sets of coaggregation partners Streptococcus spp. and Actinomyces spp., two of initial colonizing general on enamel surfaces
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Fusobacbacteria coaggregate w/ other human oral bacteria
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Veillonella spp., Capnocytophaga spp. bind to streptococci/ actinomyces
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Each coaggregation is mediated by one or more complementary sets of adhesin-receptor pairs
Coaggregation:
CoAggregation Competition:
- Competition occurs when multiple cell types recognize the same coggregation indicator mediator on the common coaggregation partner
Ecological Succession:
Process by whereby a microbial population undergoes a continuous series of changes in composition as different species colonise and become established at the expense of others. |
As conditions change, the dominant m/o's will either adapt and be retained or will be superseded by a new species better equipped to survive the altered environment.
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