sem 1 definitions - lectures 8-16 Flashcards
streptococcus
gram + cocci
catalase negative
oral streptoccoi
largest single group of bacteria isolated from the mouth and can be cultivated from all oral sites
alpha hemolysis (streptococci)
partial hemolysis of blood agar plates
green
most oral streptococci
Beta- haemolysis (pathogenic streptococci)
complete hemolysis on blood agar plates
clear haemolysis
S.pyogenes
gamma haemolysis (enterococci)
no haemolysis
streptococcus mutans
leading cause of tooth decay
carbohydrate –> acid –> demineralize enamel
acidogenic
produce acid at a high rate from sugar
aciduric
tolerate high concentration of acids
list three types of oralis streptococci
S. sanguinis
S. Oralis (bacterial endocarditis)
S.gordonii
prophylaxis antibiotics
used for at risk patients 1 hour before dental treatments
no longer recommeneded by NICE
lactobacilli (gram +)
after streptococci lactobacilli is the most important group of bacteria in dental caries
homlactic fermenter
produces one product of fermentation - lactic acid
heterolactic fermenters
produces more than one fermentation product
lacto bacilli and dental caries
lactobacilli tend to increase as mustans streptococci fall
actinomyces
gram + pleomorphic rods
major proportion of microflora
some posses fimbrae which aid in adherance and aggregation
charateristis of pus
thick fluid expressed from the sinuses
known as sulphur granules
- aggtegations of actinomyces filaments
list the 4 oral gram -ve bacteria (main groups)
- cocci
- strict anaerobes
- facultative anaerobes (capnophilic (CO2) )
- curved rods
Moraxella catarrhalis
gram -ve bacteria
- a commensal of the mouth and upper resp tract
- infects tonsillar B cells
- Meningitis, endocarditis
- most strains produce a Beta-lactammase which complicates antibiotic therapy
Black Pigmented Bacteria
- iron requiring
- porphyrins on surface
- treatment with blue light
excitation produces reactive O2 species - destroys lipids, proteins, nuclei acids
capnophilic
like co2
spirochaetes
gram -ve cell wall
helical bacteria
usually assocoicated with deep periodontal pockets
numbers increase dramatically in periodontitis
congenital syphilis
vertical transmission mother to infant
treatment : penicillin
T.denticola (spirochaete)
- most proteolytic member of the red complex
- can attach to gingival fibroblast and induce cytotoxicity and cell death
Acute necrotising ulcerative gingivitis
- An acute painful true infection of the gingivae
- A fuso-spirochaetal complex - fusobacterium nucleatum & treponema vincentii
treatment: short course of Antibiotics: metronidazole
Vincents angina ulcer
historical description of AUG
unilateral sore throat
dental plaque
plaque is the general term for the microbial community found on the tooth surface
biofilm
name given to microbial communities attached to a surface
organic matrix in dental pl
extracellular polymeric substance
30% of total plaque volume
acquired pellicle
the layer of material acquired by a cleaned tooth
types of adhesion seen in dental plaque
cell-substratum
homotypic - cell - cell adhesion
heterotypic cell-cell adhesion
bacteriocin
a substance released by one bacteria that kills another usually by inducing a metabolic block
antibiotics
a drug used to treat or prevent infection caused by micro-organisms
bacteriostatic
inhibit the growth of bacteria
bacteriocidal
kill bacteria
