In the treatment of infective endocarditis caused by viridans group streptococci, what is the first-line antibiotic?

The first-line antibiotic for the treatment of infective endocarditis caused by viridans group streptococci is Penicillin G. This is due to the organism's susceptibility to penicillin, which is effective at eradicating the bacteria responsible for this type of endocarditis.

Viridans group streptococci, which commonly includes species like Streptococcus mitis and Streptococcus sanguinis, are typically sensitive to penicillins. Penicillin G is a beta-lactam antibiotic that specifically targets the cell wall synthesis of these bacteria, leading to cell lysis and death. The recommended dosages and treatment regimens of Penicillin G align with established clinical guidelines, ensuring optimal outcomes for patients suffering from this infection.

Other options like ceftriaxone may also have activity against viridans group streptococci; however, they are not the preferred first-line treatment in most cases. Doxycycline is generally not recommended for treating viridans group streptococci endocarditis, as its spectrum of activity is not as effective in this particular context. Vancomycin, while useful for resistant bacteria, is usually reserved for cases where there is a concern for methicillin-resistant Staphylococcus aureus