Gut microflora & disease Flashcards
what diseases can be caused by a build up on dental plaque
Dental plaque inflammation leads to gingivitis and periodontal disease
Gingivitis - healthy gumline to inflammed, causing bleeding
Periodontitis - when gingivitis runs out of control, severe gum attack and erosion, causes teeth to fall out
oral health is an equilibrium between ….
between endogenous bacteria and the oral defense system
what oral bacteria are acquired in the hours after birth
Streptococcus spp. e.g. S. salivarius
what does acquisition of oral flora depend on after birth
Acquisition of oral flora depends upon exposure at the time of birth, cesarean or vaginal. Shortly thereafter, breastfeeding and environmental factors.
what oral flora are acquired in the first year of a babies life
streptococci, staphylococci, lactobacilli, Neisseria, Veillonella, Actinomyces, Fusobacterium spp.
what bacteria colonise the teeth and gingiva when teeth appear in the first year
Streptocococcus mutans and Streptococcus sanguis
what are the main stages/changes in oral flora in later life
- After tooth eruption: organisms favouring hard tissue e.g. Strep. sanguis and Strep. mutans, Actinomyces spp.
- Colonisation of crevicular tissues: anaerobic organisms e.g. Prevotella spp.
- Loss of teeth: “a 2nd childhood microflora” – alterations in flora
- Prosthetic appliance: e.g. dentures - similar to enamel plaque, may harbor large numbers of yeast
how many species can be isolated from dental plaque
> 300
how many bacteria are shed in saliva per day
10^8 bacteria/day
what are two important dental diseases
• Caries: associated with high sugar diet and poor hygiene, Holes in teeth, malodour etc
• Periodontal diseases
1. non-destructive Gingivitis: poor hygiene, Inflamed, bleeding gums
2. destructive Periodontitis: usually as get older unless very poor dental hygiene, Gum and bone loss
what are the virulence factors produced by streptococci in carious plaque
• Saccharolytic – metabolise sugars
• Glucosyltransferases – EPS glucan, mutan (insol) – plaque biofilm
• Fructosyltransferases – EPS fructan, inulin (insol) – plaque biofilm
• Acidogenic – fermentation sugars to acid (to lactic, acetic, formic acids - lower pH
• Aciduric – metabolise and grow at low pH
(low pH decalcifies hydroxyapatite enamel)
what gram negative bacteria is thought to help slow development of dental caries
Veillonella - converts lactic acid of other species to less acidic products
whta two bacteria are microbial indicators of a disease state when found in increased numbers in plaque
Lactobacillus and S. mutans
what bacteria causes acute necrotising ulcerative gingivitis
anaerobic Prevotella intermedia, Fusobacterium, Treponema and Borrelia spp.
what are the big 3 bacteria that cause periodontitis
Treponema denticola
Porphyromonas gingivalis
Aggregatibacter actinomycetemcomitans
what two bacteria make up the corn cobs found in the famous photo of dental plaque
Bacterionema matruchotii and Streptococcus sanguis - Streptococci produce lactic acid and Bacterionema converts it to butyric acid as its food source (rudimentary food chain)
what is the acquired pellicle
a protein film that forms by selective binding of glycoproteins from saliva that prevents continuous deposition of salivary calcium phosphate. It forms in seconds after a tooth is cleaned, or after chewing.
what signalling molecules do gram +ve oral bacteria use for intraspecies communication
competence stimulating peptides, which help promote single-species biofilm formation. (quorum sensing)
what cell-cell signalling molecule mediates interspecies quorum sensing to stimulate plaque formation
4, 5-dihydroxy-2, 3-pentanedione (DPD), also called Autoinducer-2 (Al-2)
what are the pioneer species of plaque
streptococci
if you cant prevent biofilm formation what antipathogen strategies can be used prevent periodontal pathogens joining the biofilm
attachment blockers and detachment signals
what type of tehcnique was used in the human microbiome project and what did they test
- Use molecular metagenomic techniques
* Testing nasal, oral, skin, gastrointestinal and urogenital colonies
what morphological characteristics does helicobacter pylori have
Spiral helical shape with lots of flagella on one end.
what diseases does helicobacter pylori cause and how
penetrates mucin lining and produces urease to neutralise acid pH. Causes stomach ulcers and stomach cancer.
