1. Which organism is most frequently found in drug addicts with infective endocarditis?
Answer: Staphyloccus aureus is the most frequent organism found in drug addicts along with other skin contaminants.

2. What is the most frequent final outcome of this disease in drug addicts with antibiotic treatment and valve replacement?
Answer: There is a very high mortality rate in drug addicts that develop acute bacterial endocarditis despite antibiotic treatment and valve replacement.

3. Give cardiac and extracardiac complications of infective endocarditis?
Answer: The complications of infective endocarditis include cardiac failure, disseminated infection, systemic embolization (which can secondarily cause myocardial, splenic, cerebral, renal infaction) and cardiac arrythmias.

4. What is the minimum number of blood cultures required to arrive at a definitive diagnosis?
Answer: The recommendation is at least 2 blood cultures, 15-60 minutes apart for a given febrile episode.

5. Compare marantic with infective endocarditis, clinically and histologically.
Answer: The vegetations seen in marantic (nonbacterial thrombotic) exhibit small bland vegetations, usually attached at the line of closure of the valve leaflets. They consist of fibrin and platelets with no inflammation or microorganisms. They are seen in association with malignancy or other debilitating disease and generally occur on normal cardiac valves. The vegetations in infective endocarditis are large irregular masses on the valve cusps that can extend onto the cords. They consist of fibrin, platelets, inflamatory cells and bacteria. They can present clinically as acute or subacute endocarditis. They can occur on normal or abnormal cardiac valves, the former being more characteristic of acute endocarditis