What is the first-line treatment for endocarditis caused by a native valve?

The first-line treatment for endocarditis caused by a native valve involves the use of Vancomycin when a patient is at risk for Methicillin-resistant Staphylococcus aureus (MRSA), as it covers Gram-positive cocci, including MRSA. Endocarditis typically arises from bacteremia due to bacteria that can colonize heart valves, and Staphylococcus aureus is a common culprit in cases affecting native valves.

In cases of endocarditis, the treatment needs to account for the possibility of resistant organisms and the urgency to provide broad-spectrum coverage, which Vancomycin effectively offers. It is particularly important in patients with risk factors such as previous MRSA infections or those who are known to be at higher risk due to other conditions or previous antibiotic exposures.

While other options like Amoxicillin are effective for certain cases of endocarditis, particularly those caused by organisms like Streptococcus viridans, they do not cover resistant strains. Therefore, Vancomycin's broad activity against resistant Gram-positive bacteria makes it the preferred first-line therapy for suspected cases of endocarditis associated with native valves.