BACTERIA COMMONLY RESPONSIBLE FOR INFECTIVE ENDOCARDITIS

Question 1

The following bacteria are common agents of endocarditis:

Answer 1

S. aureus
S. viridans
S. epidermidis
Enterococcus
S. bovis

Question 2

How does S. aureus cause endocarditis?

Answer 2

Most common cause of acute endocarditis — damage to a healthy heart
o Normal skin flora introduced through broken skin barrier
❖ Intravenous drug abuse
❖ Infected abscess
❖ Contamination during surgery or catheterization procedures

Question 3

How does S. viridans cause endocarditis?

Answer 3

Most common cause of subacute endocarditis — damage to a weak heart with
congenital heart defects
o Normal oral flora introduced by a breach in the oral mucosa
❖ Dental procedures
❖ Poor oral hygiene

Question 4

How does S. epidermidis cause endocarditis?

Answer 4

Most associated with infections of prosthetic heart valves
o Normal skin flora introduced through broken skin barrier
❖ Cardiac catheterization procedures
o Often requires surgical intervention to treat

Question 5

How do enterococcus and S. bovis cause endocarditis?

Answer 5

Subacute, nosocomial infections
o Normal GI/genitourinary flora introduced via exacerbated infection or malignancy