2.4

Question 1

The S anginosis group

Answer 1

(called S milleri group in the UK)

	- S Anginosis 
	- S constellatus 
	- S intermedius

Question 2

The S anginosis group disease implications

Answer 2

• Predilection to cause abscesses
  § Dental and head and neck region
  § Brain, spinal cord, epidural space
  § Liver
  § Peritoneal, pelvic space
  § Thoracic - lung, pleural, mediastinal
  § May also cause bacteraemia and endocarditis (usually prosthetic valves)

Question 3

2. The S mutans group

Answer 3

• S mutans and other species
  - The leading cause of dental caries
  - Attaches to tooth enamel and forms ‘slime’ (biofilm)
  - Cleaves sucrose to fructose and glucose
  - Glucose converted to dextran polymer which becomes the basis of dental plaque
  - Glucose also converted to lactic acid which decalcifies enamel leading to dental caries
  - May cause endocarditis if it enters the blood stream

Question 4

3. The S mitis group

Answer 4

• S mitis and other species

Question 5

dental caries caused by

Answer 5

S mutans

Question 6

virulence factor of S mutant

Answer 6

• Attaches to tooth enamel and forms ‘slime’ (biofilm)

Question 7

how dental plaque is made

Answer 7

• Cleaves sucrose to fructose and glucose
  - Glucose converted to dextran polymer which becomes the basis of dental plaque
  - Glucose also converted to lactic acid which decalcifies enamel leading to dental caries

Question 8

S mitis causes

Answer 8

• Can cause infective endocarditis
  § Susceptible valves are either native valves with a pre-existing abnormality of prosthetic valves
  § Commonest bacterial causes of non-hospital acquired endocarditis
  □ S mitis in particular
  § Typically enter blood stream following minor oral trauma eg. Dental work
  § Infective emboli may break off from these vegetations and travel through the bloodstream to establish abscesses in other organs (eg. Brain)
  Bacterial endocarditis, if untreated has a near 100% mortality

Question 9

Commonest bacterial causes of non-hospital acquired endocarditis

Answer 9

S mitis group, S mitis in particular

Question 10

4. The S salivarius group

Answer 10

• S salivarius and other species
  - This member of the oral flora of the mouth is an uncommon cause of invasive disease
  - There is growing evidence of its role as an uncommon cause of meningitis

Question 11

The S bovis group

Answer 11

(These express the Lancefield group D antigen)

	- S bovis and other species 
	- Normal flora of the GI tract 
	- May enter the bloodstream causing bacteraemia and septicaemia 
	- May also cause bacterial endocarditis 
	- Finding this in the bloodstream is strongly associated with underlying, often undiagnosed, colonic malignancy 
	- Agglutinate with Lancefeild D antisera

Question 12

S bovis group are normal flora of

Answer 12

the GI tract

Question 13

S Boris group agglutinate with

Answer 13

group D antisera

Question 14

finding S Bovis in the blood stream indicates

Answer 14

• Finding this in the bloodstream is strongly associated with underlying, often undiagnosed, colonic malignancy