Infective Endocarditis

Most common causative agents of infective endocarditis?

Staphylococcus aureus, Staphylococcus epidermidis, viridans streptococci, enterococci. (Normal bacteria of mouth)

What is the pathogenesis of infective endocarditis?

Bacteria enter the blood → attach to damaged heart valves → form biofilms → continuously shed into blood → septic emboli break off and block vessels → tissue damage, stroke, heart failure, and immune complex inflammation.

What allows infective endocarditis bacteria to survive on heart valves?

The bacteria form a protective biofilm, which shields them from antibiotics and the immune system.

How do bacteria enter the bloodstream in infective endocarditis?

Through dental procedures, tooth brushing, trauma, IV drug use, or indwelling catheters.

Why do damaged heart valves increase the risk of infective endocarditis?

Bacteria can become trapped in small blood clots that form on abnormal or damaged valves.

What is an aneurysm in infective endocarditis?

A weakened blood vessel wall that balloons outward due to infection.

How can infective endocarditis damage the kidneys?

Antigen-antibody immune complexes can lodge in the kidneys and cause glomerulonephritis.

Infective Endocarditis Epidemiology

Higher risk in people with:

• IV catheters

• Prosthetic heart valves

• IV drug use

Most common pathogens:

• Staphylococcus aureus

• Staphylococcus epidermidis

• Enterococci

• Viridans streptococci

Major risk factors for infective endocarditis

IV drug use, indwelling catheters, and prosthetic heart valves.

What is the treatment for infective endocarditis?

Treatment requires prolonged intravenous antibiotics chosen based on the pathogen's antibiotic susceptibility, usually for more than one month. Surgery may be needed if heart valves are severely damaged or if biofilm-covered devices must be replaced.

Why can infective endocarditis be difficult to treat?

Bacteria form biofilms on heart valves and medical devices, which protect them from antibiotics and the immune system.

When is surgery needed for infective endocarditis?

When heart valves are damaged or when infected devices covered with biofilms need to be removed or replaced.

How can infective endocarditis be prevented?

Use sterile technique when inserting catheters, move or remove catheters as soon as possible, and reduce unnecessary bloodstream infections.

Who may receive prophylactic antibiotics to prevent infective endocarditis?

People at highest risk, such as those with artificial heart valves or a history of infective endocarditis.