Does Viridans streptococcus (VSS) bacteremia require an echocardiogram (echo)?

From the Guidelines

Patients with Viridans streptococcus bacteremia should undergo echocardiography to evaluate for infective endocarditis, as recommended by the 2015 ESC guidelines for the management of infective endocarditis 1. The recommendation for echocardiography in patients with Viridans streptococcus bacteremia is based on the potential for these bacteria to cause infective endocarditis, particularly in patients with underlying valvular heart disease.

• The European Society of Cardiology guidelines suggest that transthoracic echocardiography (TTE) is the first-line imaging modality in suspected infective endocarditis, with transoesophageal echocardiography (TOE) recommended in patients with a negative or non-diagnostic TTE, or when a prosthetic heart valve or intracardiac device is present 1.
• The guidelines also recommend repeat TTE and/or TOE within 5-7 days in case of initially negative examination when clinical suspicion of infective endocarditis remains high 1.
• Echocardiography should be considered promptly, ideally within 24-48 hours of identifying the bacteremia, even in the absence of clinical signs of endocarditis, as findings may alter management decisions, including antibiotic selection and duration.
• If endocarditis is confirmed, treatment typically involves 4-6 weeks of intravenous antibiotics, with specific regimens based on antimicrobial susceptibility testing, and surgical consultation should be considered for patients with complications such as heart failure, persistent bacteremia, or large vegetations.

From the Research

Viridans Streptococcus Bacteremia and Echocardiogram Requirement

• The decision to perform an echocardiogram in patients with Viridans streptococcus (VSS) bacteremia depends on various risk factors, including heart valve disease, persistent bacteremia, age, and underlying malignancy 2.
• A study published in 2024 identified independent risk factors for infective endocarditis (IE) in patients with VGS bacteremia, which included heart valve disease, persistent bacteremia, younger age, and absence of underlying malignancy 2.
• The same study suggested that echocardiographic evaluation could be prudently considered based on these clinicomicrobiological risk factors 2.
• Another study published in 2018 reported a case of infective endocarditis with Streptococcus viridans associated with fixed orthodontic appliance, highlighting the importance of identifying possible pre-existing cardiac conditions and monitoring patients with echocardiography 3.
• The American Heart Association's guidelines for the treatment of infective endocarditis were discussed in a 2008 study, which reported a case of endocarditis due to a penicillin-resistant Streptococcus parasanguinis 4.
• A 2010 study emphasized the importance of antibiotic prophylaxis in patients with mitral valve prolapse, even if they are considered low-risk, to prevent subacute bacterial endocarditis (SBE) 5.
• The antimicrobial susceptibility pattern of Viridans group Streptococci isolated from blood samples of infective endocarditis patients was studied from 2018 to 2023, highlighting the emergence of resistance to beta-lactam agents like penicillin 6.

Key Considerations

• Heart valve disease is a significant risk factor for IE in patients with VGS bacteremia 2.
• Persistent bacteremia and younger age are also independent risk factors for IE in these patients 2.
• Echocardiographic evaluation should be considered based on clinicomicrobiological risk factors 2.
• Antibiotic prophylaxis is crucial in preventing SBE in patients with mitral valve prolapse, even if they are considered low-risk 5.