A patient with possible infective endocarditis presents with Janeway lesions. Which treatment regimen is indicated?

In cases of suspected infective endocarditis, particularly when Janeway lesions are present, it is crucial to select an appropriate antibiotic regimen that targets the likely pathogens involved, primarily Staphylococcus aureus and Streptococcus viridans.

The combination of Penicillin G and nafcillin is indicated due to its efficacy against these common organisms. Penicillin G is effective against susceptible Streptococci, while nafcillin effectively targets methicillin-sensitive strains of Staphylococcus aureus (MSSA). This regimen offers a synergistic approach for treating endocarditis associated with these organisms, addressing the prevalent bacterial infections that typically cause this condition.

This choice is optimal for most cases of infective endocarditis, particularly when there is no identified resistance or specific allergy. The other regimens, while effective in certain scenarios, may not provide the best coverage or may involve unnecessary additional complexity in the treatment. For instance, vancomycin plus gentamicin is often used for more resistant strains or in patients with more complex needs. However, targeting common pathogens in uncomplicated cases with penicillin and nafcillin is both effective and straightforward.