From the Guidelines
Echocardiography is recommended for all adult patients with bacteremia, particularly those with positive blood cultures for Staphylococcus aureus, HACEK organisms, Candida species, and other fungi, as well as those with prosthetic heart valves, implantable cardiac devices, congenital heart disease, or a history of previous endocarditis. The rationale for this recommendation is based on the higher propensity of these organisms to cause endocarditis and valvular damage, as well as the importance of early detection and treatment to reduce morbidity and mortality 1.
Key Organisms Requiring Echocardiogram
- Staphylococcus aureus
- HACEK organisms (Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, and Kingella)
- Candida species
- Other fungi
- Streptococcus viridans group
- Enterococcus species
Patient Groups Requiring Echocardiogram
- Patients with prosthetic heart valves
- Patients with implantable cardiac devices
- Patients with congenital heart disease
- Patients with a history of previous endocarditis
- Patients with persistent bacteremia (positive cultures after 48-72 hours of appropriate antibiotic therapy)
- Patients with bacteremia without an identifiable source
Preferred Echocardiography Method
- Transesophageal echocardiography (TEE) is generally preferred over transthoracic echocardiography (TTE) due to its higher sensitivity for detecting vegetations and perivalvular complications, particularly in patients with prosthetic valves or when TTE images are suboptimal 1.
Importance of Early Detection
Early detection of endocarditis through echocardiography allows for appropriate antibiotic duration (typically 4-6 weeks for endocarditis versus 2 weeks for uncomplicated bacteremia) and timely surgical intervention if needed, which can significantly improve patient outcomes in terms of morbidity, mortality, and quality of life 1.
From the Research
Types of Positive Blood Cultures Requiring Echocardiogram
- Staphylococcus aureus bacteremia is a type of positive blood culture that requires a recommended echocardiogram, as it can lead to endocarditis and other metastatic infections 2
- Patients with Staphylococcus aureus bacteremia should undergo transthoracic echocardiography, and transesophageal echocardiography should be performed in patients at high risk for endocarditis, such as those with persistent bacteremia, persistent fever, metastatic infection foci, or implantable cardiac devices 2
- A single positive blood culture with Staphylococcus aureus can be clinically significant and may require an echocardiogram to rule out endocarditis, especially if the patient has risk factors such as intravascular devices, recent surgical procedures, or injection drug use 3
- The clinical significance of a single positive blood culture with Staphylococcus aureus is unclear, but it can be associated with a higher risk of infective endocarditis and mortality compared to patients with multiple positive blood cultures 3
- Perivalvular abscesses are a major complication of infective endocarditis caused by Staphylococcus aureus, and transesophageal echocardiography has a higher incremental value in detecting this complication compared to transthoracic echocardiography 4
- Follow-up blood cultures are important in patients with a single Staphylococcus aureus-positive blood culture to manage the infection properly and prevent relapse, and an echocardiogram may be recommended if the follow-up blood cultures are positive 5
- A single positive blood culture with Staphylococcus aureus can represent either true bacteremia or contamination, and an echocardiogram may be recommended to rule out endocarditis, especially if the patient has risk factors or clinical symptoms suggestive of endocarditis 6