Bacteremia, septicaemia and endocarditis
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Bacteremia, septicaemia and endocarditis by Dr. Rakesh Prasad Sah
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Bacteremia, septicaemia and endocarditis
- 1. Bacteraemia, Septicaemia and Infective Endocarditis Dr. Rakesh Prasad Sah Assistant Professor, Microbiology
- 2. • Refers to presence of microorganisms in blood threat to every organ in the body • M.Os. Invasion of blood serious consequences shock, multiple organ failure and DIC • All four categories of microbes (Bacteria, Viruses, fungi and parasites) can cause BSI. Introduction
- 3. • Bacteraemia +ce of bacteria in blood without any multiplication. • Septicaemia bacteria circulate & actively multiply in the bloodstream. • Pyaemia septicaemia caused by pyogenic bacteria with multiple abscesses in internal organs such as spleen, lungs, liver, kidneys, brain, heart etc. • Toxaemia formation of toxic products in the blood • When bacterial endotoxin circulates in the blood, the condition is called endotoxaemia.
- 4. Causative agents of Septicaemia GNB (Gram negative Bacilli) (60-70%) 1 Salmonella typhi 2 Salmonella paratyphi A 3 Salmonella paratyphi B 4 Salmonella paratyphi C 5 Brucella spp. 6 Haemophilus influenzae 7 Escherichia coli 8 Klebsiella pneumoniae 9 Proteus spp. 10 Enterobacter spp. 11 Bacteroides spp. 12 Pseudomonas spp. GPC (Gram Positive cocci) (20-40%) 1 Staphylococcus aureus 2 Staph. epidermidis 3 Streptococcus pyogenes 4 Str. pneumoniae GPB (Gram Positive bacilli) 1 Listeria monocytogenes GNC (Gram negative cocci) 1 Neisseria meningitidis
- 5. • Bacteria may entre bloodstream: – From an infective focus with the help of phagocytic cells carrying microbes in to capillaries or the lymphatic system – From breakages of blood vessels adjacent to the skin or mucosal surfaces. – By introduction of contaminated material directly into the vascular system. Pathogenesis
- 7. Clinical Features • Fever or hypothermia • Rigors • Tachycardia • Tachypnoea • Hypoxia • Dyspnoea • Cynosis • Hypotension • Mental Confusion • Agitation • Behavioural changes
- 8. Complications • Septic • Endotoxic • Bacteraemic shock • DIC • Acute renal failure • Shock may lead to multiple organ failure (e.g. heart, lungs, liver, kidneys) Most common complication Complications
- 9. • Septic Shock inadequate blood supply to the tissue (hypotension) reduces tissue perfusion pressure tissue hypoxia ischemia and organ dysfunction.
- 10. • Endocarditis is the infection of the endocardium of heart valves. • Inf. inflammation of membrane lining of the heart. • Bacterial endocarditis bacterial inf. Of heart valves • Mortality rate was very high before pre-antibiotic era • Even now, mortality rate is around 20-50% despite Antibiotics. Infective Endocarditis
- 11. Predisposing factors of Endocarditis Endocarditis Congenital defects, e.g. bicuspid aortic valve, septal defects, patent ductus, arteriousus, coarctation of tha aorta Rheumatic valvular ds, e.g. stenosis or incompetence of the mitral and aortic valves following rheumatic fever Intra-cardiac prostheses, e.g. replacement of disease heart valves Intravenous drug abuse Degenerative cardiac diseases, e.g. calcific aortic stenosis, syphilitic aortic valve disease
- 12. 1. Subacute endocarditis 2. Acute endocarditis 3. Postoperative endocarditis 4. Endocarditis associated with intravenous drug abuse Clinical Types
- 13. • 70% of cases • Chronic course • Organisms of low virulence • On damaged or defective valve cusps • Form large firm vegetation comprising of dense fibrin, platelets aggregates with bacterial colonies are formed. Subacute endocarditis
- 14. • Bacteria – Streptococcus sanguis – Str. Mutans – Str. Mitis – Enterococcus faecalis – Staph. Epidermidis – Coxiella burnetti – Chlamydia psittaci • Fungi – Candida albicans – Aspergillus spp. Causative agents Subacute Endocarditis Responsible for 60-80% of cases
- 15. • Rapidly progressive ds highly virulent pyogenic bacteria • Tricuspid valve more commonly affected. • If not treated fatal (less than 6 weeks) Causative agents • Staphylococcus aureus • Streptococcus pneumoniae • Other pyogenic cocci – Str. Pyogens – Str. Agalactiae (group B) Acute endocarditis
- 16. • Following cardiac surgery in prosthetic valve replacement. • Causative agents – Staphylococcus epidermidis (most commonest) – Stphylococcus aureus – Candida albicans – Acinetobacter calcoaceticus Post-operative endocarditis
- 17. • Higher risk • Tricuspid valve (common) • Skin is the commonest source of infection • Causative agents – Staphylococcus aureus (most commonest) – Others include • Viridans group of streptococci • Candida spp. • Pseudomonas spp. Endocarditis associated with IV drug abusers
- 18. • 3-6 samples of blood, 10ml should be collected over 24 hrs. • Before starting antimicrobial therapy • From antecubital vein under all aseptic conditions using sterile disposable syringe. • Inoculated into 50-100ml of glucose broth • Large amount of media is required because: – Number of organisms in the blood may be very few and – The blood may contains bactericidal substances which are diluted by large volume of medium. Lab Diagnosis
- 19. • Cultures are incubated at 370C for at least 3 weeks and are to be observed daily for early signs of growth. • S/c on B.A. & M.A. (24hrs, 48hrs & 1ce in a week) incubation isolated colony morphology, Gram staining, biochemical rxn and serological tests. AST by MIC & MBC for ensuring the serum levels penetrate valves and kills organisms. Culture
- 20. • 10-20% cases • Following resons – Recent antibiotic therapy – Inadequate no. of samples – Infection with Coxiella burnetti or Chlamydia spp. • OTHER TESTS – TLC – ESR – Echocardiogram Culture Negative Endocarditis
- 21. • Good dental hygiene • Prophylactic antibiotic before dental extraction or other surgical procedure. Prevention