Endocarditis Due toStreptococcus mitiswith High-Level Resistance to Penicillin and Cefotaxime

To the Editor: Levitz reported (June 10 issue)1 on the successful use of intravenous vancomycin for treatment of a patient who had endocarditis caused by a penicillin-resistant strain of Streptococcus mitis. We treated a 48-year-old man with native-valve endocarditis due to penicillin- and cefotaxime-resistant S. mitis. He had a history of human immunodeficiency virus infection, injection-drug use, severe aortic insufficiency, and moderate mitral regurgitation. In the previous year, the patient had undergone several dental procedures. For prophylaxis against endocarditis, he received 3 g of amoxicillin one hour before each dental procedure and 1.5 g six hours after each procedure. His . . .