[A case of infective endocarditis (IE) improving with orally administered amoxicillin (AMPC)]

Progress in chemotherapy and cardiosurgery has remarkably decreased the mortality due to infective endocarditis (IE) in recent years. In chemotherapy for IE, parental administration of antibiotics has been used routinely, the patients suffer from the psychological and physiological burden due to frequent injections and long period of therapy, even though the therapy for IE is successful. In this report, we present a case of IE caused by S. mitis, which was remarkably improved by oral administration of AMPC. A case, 69. y.o. female. She felt like a common cold and visited a G.P. Cardiomegaly was pointed out and positive inflammatory findings in serological examination were found. A low grade fever continued, and she was admitted to the hospital. Blood cultures were positive for S. mitis. For further examination, she was transferred to the university hospital. Based on the extensive blood cultures and cardioechogram, she was diagnosed IE caused by S. mitis. Because there were no symptoms of heart failure, we decided to try oral administration of AMPC, 4 g/day or 6 g/day at an interval of 6 hours. On the second day of therapy, the blood culture turned to be negative for pathogens, and on the fourth day body temperature became normal. On about the 60th day, the CRP finding became negative. Concentrations in the serum of AMPC were more than 10 folds of AMPC-MIC (0.5 microgram/ml) for S. mitis. The patient, however, suffer from complications of lung embolism and was operated for exchange of heart valves. After surgery, she has been well without any symptoms from IE.