1. Extraoral infections caused by oral bacteria Endocarditis

2. Infective endocarditis Infection of endocardium acute acute subacute subacute chronic chronic About 2 to 3 out of 100,000 people develop bacterial endocarditis each year in the US

3. Risk factors Defective valves Defective valves Prosthetic valves Prosthetic valves Congenital heart defects e.g. Congenital heart defects e.g. Ventricular septal defect Ventricular septal defect Patent ductus arteriosus Patent ductus arteriosus

4. Causative organisms Viridans streptococci (50%) Viridans streptococci (50%) (S. mutans, S. sanguis) Staphylococcus aureus Staphylococcus aureus Enterococcus faecalis Enterococcus faecalis More uncommonly other bacteria, fungi More uncommonly other bacteria, fungi

5. Pathogenicity Bacteremia Bacteremia Biofilm along valve edges Biofilm along valve edges Infectious organisms Infectious organisms Mass of fibrin Mass of fibrin Platelets Platelets

6. Clinical Features Valve destruction  heart failure Valve destruction  heart failure Embolic events  abscesses in brain, liver Embolic events  abscesses in brain, liver Immune complex deposition  vasculitis Immune complex deposition  vasculitis  arthralgia  arthralgia  glomerulonephritis  glomerulonephritis Malaise, fever, night sweats, weight loss, anaemia Malaise, fever, night sweats, weight loss, anaemia

7. Diagnosis  Blood cultures – repeated samples  Anaemia   white blood cell count   erythrocyte sedimentation rate  Echocardiography

8. Mortality Fatal if untreated Fatal if untreated 6% sensitive streptococci 6% sensitive streptococci 30% Staphylococcus aureus 30% Staphylococcus aureus

9. Management Antibiotics i.v. Antibiotics i.v. (penicillin and gentamicin before AST results) (penicillin and gentamicin before AST results) Oral antibiotics Oral antibiotics

10. Bacteremia

11. Frequency of bacteremia Procedure% Extraction10-100 Scaling and root planing 8-80 Rubber dam matrix/wedge placement 9-32 Tooth brushing and flossing 20-68 Chewing food 7-51

12. Magnitude of bacteremia Dental procedures <10 4 CFU/ml Routine daily activities <10 4 CFU/ml Experimental endocarditis 10 6 – 10 8 CFU/ml

13. Persistance of bacteremia Most positive blood cultures were within 10 mins after extraction. Most positive blood cultures were within 10 mins after extraction. 6-30 minutes with single extraction 6-30 minutes with single extraction Only a small no. of positive blood cultures between 30-60 minutes Only a small no. of positive blood cultures between 30-60 minutes

14. Control and prevention Oral hygiene Oral hygiene Antibiotics Antibiotics

15. Dental procedures All dental procedures that involve manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa, All dental procedures that involve manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa, e.g. e.g. Extraction Extraction Periodontal probing, scaling, root planing and surgery Periodontal probing, scaling, root planing and surgery Biopsy Biopsy Suture removal Suture removal Subgingival restorations Subgingival restorations Orthodontic band placement Orthodontic band placement

16. ATB One hour pre-operation One hour pre-operation Amoxycillin Amoxycillin If penicillin allergic, clindamycin 600mg po If penicillin allergic, clindamycin 600mg po Allergic to penicillin and unable to swallow capsules, azithromycin 500mg po Allergic to penicillin and unable to swallow capsules, azithromycin 500mg po Alternatively intravenous options Alternatively intravenous options Pre-operative chlorhexidine (0.2%) mouthrinse Pre-operative chlorhexidine (0.2%) mouthrinse

17. Amoxycillin Drug of 1 st choice Drug of 1 st choice Well absorbed from GIT Well absorbed from GIT High serum concentrations High serum concentrations Few side-effects Few side-effects BUT increasing resistance to penicillin BUT increasing resistance to penicillin in viridans streptococci

18. Adverse reactions Check for drug allergy Check for drug allergy Check for antibiotic treatment in last 4 weeks Check for antibiotic treatment in last 4 weeks If patient is on other drugs, antibiotics may interfere with. If patient is on other drugs, antibiotics may interfere with.