Streptococcus cristatus, an infrequent cause of bacteremia and infective endocarditis. Case report and literature review.

A transthoracic echocardiogram (TTE) showed thickening of the aortic prosthesis leading to mild aortic insufficiency and concentric left ventricular hypertrophy with LVEF 53%. Given the high suspicion of infective endocarditis (one major and two minor criteria), a transesophageal echocardiogram (TEE) was performed, with thickened and calcified leaflets, mild posterior periprosthetic regurgitation, although without stigmata of endocarditis. Although not confirmed by imaging tests, the patient received ceftriaxone (2 g/24 h) for possible infective endocarditis for 6 weeks with two subsequent negative blood cultures.