Bacteria Flashcards
During plaque formation what are they initial colonisers? What makes them good at this?
Streptococci
GTFs and adhesion molecules makes them sticky
What were the findings of the Takeuchi et al 2004 study?
The development of subgingival biofilm occurred in five sequential phases: pellicle formation, microbial adherence, initial colonization, microbial organization, and establishment. There were initial, secondary and tertiary colonizers.
What is the ecological plaque theory Marsh 1994?
Increased plaque causes increased inflammation,
which caused an environmental change (high GCF flow, bleeding, raised pH and temperature)
This causes an ecological shift from gram positive bacteria to gram negative
This causes a shift in disease from gingival health to gingivitis and periodontal disease
What were the findings of the Socransky et al 1998 study?
Sub gingival bacteria lives in complexes. Yellow and blue are early colonisers. Red and orange are predominantly anaerobes
Describe the association of p.gingivalis with perio disease
P.gingivalis is associated with an increased risk for alveolar bone loss and attachment loss
It’s numbers are decreased in health and increased in periodontal lesions
What disease is A.a associated with?
Aggressive periodontitis
Name the clone of A.a. What individuals is this mostly associated with?
JP2 clone
Northern African
What is the keystone pathogen hypothesis? What study proposed this hypothesis?
The keystone-pathogen hypothesis holds that certain low-abundance microbial pathogens can orchestrate inflammatory disease by remodelling a normally benign microbiota into a dysbiotic one
Hajishengallis et al 2011
Give an example of a keystone pathogen and explain why
P.gingivalis
It maintains and governs entire microbiome
It causes a shift from symbiotic to dysbiotic
What is the link between viruses and periodontal disease?
A study found an association between cytomegalovirus and Epstein Barr virus with periopathogenic bacteria and severity of periodontal disease
What is a dental pellicle?
Dental pellicle is a protein film that forms on the surface enamel
Describe the formation of the dental pellicle
- Starts within seconds
- It develops over 30-90 minutes
- Protein absorption by protein-protein interaction
- Electrostatic attraction to hydroxyapatite
Name some subgingival pellicle proteins
Albumin, IgA, IgG, IgM
What is a biofilm?
Bacterial species organised in complex communities
How do biofilms create bacterial resistance?
- Protection from host defence
- Protection from dessication
- Protection from antimicrobial agents (slow growth rate, poor penetration)
- Quorum sensing (communication between bacteria through channels)
Describe the association of Tanerella Forsythensis with perio disease
Increase in lesions of periodontitis Decrease in health or gingivitis Increase in progressive lesions Increase in periodontal abscesses Its presence indicates increased risk of alveolar bone loss and attachment loss
What were the main findings of the following study: “ Ximenez-Fyvie et al, 2000 - Comparison of the microbiota of supra‐ and subgingival plaque in health and periodontitis”
- Actinomyces species were the dominant taxa in both supra and subgingival plaque from healthy and periodontitis subjects
- P.gingivalis, B.forsythus and T.denticola could be detected in subgingival plaque sample of both healthy and periodontitis subjects
- The main differences between supra and subgingival plaque as well as between health and disease were in the proportions and to some extent levels of Actinomyces, “orange” and “red” complex species.
State some major bacterial activities that define periodontal disease
- Iron acquisition
- Lipopolysaccharide synthesis
- Flagellar synthesis
- Potassium uptake
