A 71-YEAR-OLD man with a history of coronary artery disease, moderate aortic stenosis, and arterial hypertension was scheduled for aortic valve replacement and possible aortic root replacement. One month before admission, he was treated for methicillin-sensitive Staphylococcus aureus endocarditis. A transthoracic echocardiogram revealed a lesion on the mitral valve that was suspected to be a vegetation associated with mild mitral regurgitation. The patient began a course of intravenous oxacillin as an outpatient.