What distinguishes Staphylococcus viridans from Staphylococcus aureus in the context of endocarditis?

The distinguishing feature of Staphylococcus viridans in the context of endocarditis is its association with subacute endocarditis. Staphylococcus viridans, which is part of the normal flora of the oral cavity, is known for its role in causing subacute bacterial endocarditis, particularly in patients with pre-existing valvular heart disease or other underlying conditions. This form of endocarditis develops slowly and can be quite insidious, often presenting with nonspecific symptoms.

In contrast, Staphylococcus aureus is more likely to cause acute endocarditis, which can affect healthy individuals and presents rapidly with severe symptoms. S. aureus is also often implicated in cases related to intravascular devices or intravenous drug use, which differentiates it clearly from S. viridans in the types of patients and contexts in which they typically present with endocarditis.

The association of Staphylococcus viridans with subacute endocarditis is a crucial factor for providers when diagnosing and treating patients with suspected infective endocarditis, as this can influence both the antimicrobial therapy chosen and the need for other interventions such as valve replacement. Understanding this distinction is essential for clinicians managing patients with heart valve infections.