From the Guidelines
Staphylococcus aureus is the most common cause of acute infective endocarditis, and coverage for this bacterium, as well as β-hemolytic streptococci, and aerobic Gram-negative bacilli, is reasonable in patients with acute clinical presentations of native valve infection. When considering the etiology of acute infective endocarditis, several bacteria can be implicated, but the most recent and highest quality evidence suggests that Staphylococcus aureus is a predominant cause, particularly in cases with acute presentations 1. Key factors to consider in the diagnosis and management of acute infective endocarditis include:
- The clinical presentation, with acute cases often being more aggressive and associated with higher complication rates
- The epidemiological factors and patient history, which can guide initial empiric antibiotic therapy
- The importance of blood cultures and echocardiography in diagnosis
- The need for consultation with an infectious diseases specialist, especially in culture-negative cases or when defining the most appropriate therapy 1. Given the potential severity and complications of acute infective endocarditis, it is crucial to initiate empiric antibiotic therapy promptly, with coverage for Staphylococcus aureus, β-hemolytic streptococci, and aerobic Gram-negative bacilli being reasonable for patients with acute native valve infections 1. Treatment regimens should be tailored based on subsequent culture results and susceptibility patterns, with the goal of achieving optimal outcomes in terms of morbidity, mortality, and quality of life.
From the Research
Causative Agents of Acute Infective Endocarditis
- The most common microorganism causing acute infective endocarditis is Staphylococcus aureus, found in 54.3% of studies 2
- Other common causes include Viridans group streptococci, coagulase-negative staphylococci, Enterococcus spp, and Streptococcus bovis 2
- S. aureus is the leading cause of infective endocarditis in the 21st century, and its epidemiology has shifted towards more healthcare-associated infections 3
Interaction between Bacteria
- Streptococcus pneumoniae can kill Staphylococcus aureus by producing membrane-permeable hydrogen peroxide (H2O2) 4
- The interaction between S. pneumoniae and S. aureus can generate ·OH radicals that rapidly kill S. aureus strains 4
- S. pneumoniae and S. aureus can induce distinct metabolic responses in pneumonia 5
Clinical Implications
- The negative association between carriage of S. aureus and S. pneumoniae has been reported in children, and the introduction of pneumococcal vaccination has shown varying clinical implications 6
- The epidemiology of infective endocarditis has changed over time, with a growing number of healthcare-associated infections, particularly seen in infective endocarditis and prosthetic device infections 3