sem 1 definitions - lectures 8-16

Question 1

streptococcus

Answer 1

gram + cocci

catalase negative

Question 2

oral streptoccoi

Answer 2

largest single group of bacteria isolated from the mouth and can be cultivated from all oral sites

Question 3

alpha hemolysis (streptococci)

Answer 3

partial hemolysis of blood agar plates
green
most oral streptococci

Question 4

Beta- haemolysis (pathogenic streptococci)

Answer 4

complete hemolysis on blood agar plates
clear haemolysis
S.pyogenes

Question 5

gamma haemolysis (enterococci)

Answer 5

no haemolysis

Question 6

streptococcus mutans

Answer 6

leading cause of tooth decay

carbohydrate –> acid –> demineralize enamel

Question 7

acidogenic

Answer 7

produce acid at a high rate from sugar

Question 8

aciduric

Answer 8

tolerate high concentration of acids

Question 9

list three types of oralis streptococci

Answer 9

S. sanguinis
S. Oralis (bacterial endocarditis)
S.gordonii

Question 10

prophylaxis antibiotics

Answer 10

used for at risk patients 1 hour before dental treatments

no longer recommeneded by NICE

Question 11

lactobacilli (gram +)

Answer 11

after streptococci lactobacilli is the most important group of bacteria in dental caries

Question 12

homlactic fermenter

Answer 12

produces one product of fermentation - lactic acid

Question 13

heterolactic fermenters

Answer 13

produces more than one fermentation product

Question 14

lacto bacilli and dental caries

Answer 14

lactobacilli tend to increase as mustans streptococci fall

Question 15

actinomyces

Answer 15

gram + pleomorphic rods
major proportion of microflora
some posses fimbrae which aid in adherance and aggregation

Question 16

charateristis of pus

Answer 16

thick fluid expressed from the sinuses
known as sulphur granules
- aggtegations of actinomyces filaments

Question 17

list the 4 oral gram -ve bacteria (main groups)

Answer 17

• cocci
• strict anaerobes
• facultative anaerobes (capnophilic (CO2) )
• curved rods

Question 18

Moraxella catarrhalis

Answer 18

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

Question 19

Black Pigmented Bacteria

Answer 19

• iron requiring
• porphyrins on surface
• treatment with blue light
  excitation produces reactive O2 species
• destroys lipids, proteins, nuclei acids

Question 20

capnophilic

Answer 20

like co2

Question 21

spirochaetes

Answer 21

gram -ve cell wall
helical bacteria
usually assocoicated with deep periodontal pockets
numbers increase dramatically in periodontitis

Question 22

congenital syphilis

Answer 22

vertical transmission mother to infant

treatment : penicillin

Question 23

T.denticola (spirochaete)

Answer 23

• most proteolytic member of the red complex

- can attach to gingival fibroblast and induce cytotoxicity and cell death

Question 24

Acute necrotising ulcerative gingivitis

Answer 24

• An acute painful true infection of the gingivae
• A fuso-spirochaetal complex - fusobacterium nucleatum & treponema vincentii

treatment: short course of Antibiotics: metronidazole

Question 25

Vincents angina ulcer

Answer 25

historical description of AUG

unilateral sore throat

Question 26

dental plaque

Answer 26

plaque is the general term for the microbial community found on the tooth surface

Question 27

biofilm

Answer 27

name given to microbial communities attached to a surface

Question 28

organic matrix in dental pl

Answer 28

extracellular polymeric substance

30% of total plaque volume

Question 29

acquired pellicle

Answer 29

the layer of material acquired by a cleaned tooth

Question 30

types of adhesion seen in dental plaque

Answer 30

cell-substratum
homotypic - cell - cell adhesion
heterotypic cell-cell adhesion

Question 31

bacteriocin

Answer 31

a substance released by one bacteria that kills another usually by inducing a metabolic block

Question 32

antibiotics

Answer 32

a drug used to treat or prevent infection caused by micro-organisms

Question 33

bacteriostatic

Answer 33

inhibit the growth of bacteria

Question 34

bacteriocidal

Answer 34

kill bacteria