Infective Endocarditis (Cardiovascular Infections)

What are the main etiologic agents of infective endocarditis?

Staphylococcus, Streptococcus, and Enterococcus.

What is a major principle of antimicrobial therapy regarding inoculum effect?

The inoculum effect indicates that some antibiotics are less effective at high bacterial densities seen in infective endocarditis.

Why is bactericidal drug therapy emphasized in infective endocarditis treatment?

Bactericidal drugs are required for vegetation sterilization.

What is typically required duration of therapy for infective endocarditis?

Prolonged therapy is usually required due to high bacterial densities within vegetation.

What barriers do bacteria face when penetrating vegetation in infective endocarditis?

Vegetation acts as a mechanical barrier composed of fibrin and platelets.

How is the total duration of therapy for infective endocarditis determined?

The count begins when blood cultures become negative.

What is the recommended method for administering regimens with multiple antibiotics?

Administer antibiotics at the same time or close together to maximize synergistic killing.

What is the first-line treatment for penicillin-susceptible native valve streptococci?

Penicillin G or Ceftriaxone for 4 weeks.

How should highly penicillin-resistant streptococci be treated?

Vancomycin for 4-6 weeks or Ampicillin with Gentamicin.

What are the typical treatments for native valve infective endocarditis caused by Staphylococcus aureus in IV drug users?

IV Beta-lactam or IV Daptomycin for 2 weeks, and IV Vancomycin for more than 2 weeks.

What is the first-line therapy for oxacillin-susceptible Staphylococcus in left-sided infective endocarditis?

Nafcillin or Oxacillin for 6 weeks.

What is the reason for preferring Nafcillin over Oxacillin for Staphylococcus treatments?

Cefazolin is more vulnerable to beta-lactamases than Nafcillin.

How are enterococci affected by beta-lactams and vancomycin?

Enterococci are inhibited but not killed by beta-lactams and vancomycin.

What is the treatment for Vancomycin-resistant enterococci (VRE)?

Linezolid or Daptomycin with or without Ampicillin or Ceftaroline.