渡辺 賢一¹, 大滝 英二², 草野 頼子¹, 宮島 静一¹

Kenichi WATANABE¹, Eiji OHTAKI², Yoriko KUSANO¹, Seiichi MIYAJIMA¹

¹燕労災病院循環器内科, ²榊原記念病院循環器内科

¹Division of Cardiology Tsubame Rosai Hospital, ²Division of Cardiology Sakakibara Heart Institute

キーワード : Color Doppler echocardiography, Infective endocarditis, Minimum bactericidal concentration, Panipenem/betamipron, Streptococcus sanguis

A 55-year-old man was hospitalized because of breathlessness and a continuous fever that had appeared about 4 weeks earlier. His condition was NYHA classification III; and he had a white blood cell count of 9700/mm³, elevated CRP, red blood cell sedimentation rate of 110 mm/hr, and positive Streptococcus sanguis in blood culture. Echocardiography showed the presence of regurgitant flows and ruptured aortic and mitral valves. Minimum bactericidal/minimum inhibitory concentrations (MBC/MIC) of benzyl penicillin and panipenem/betamipron (Carbenin®, PAPM/BP) were 12.5/0.05 μg/ml and 0.025/0.025 μg/ml, respectively. The diagnosis was active infective endocarditis caused by penicillin-tolerant S. sanguis. The infection was treated with daily intravenous administration of 10 million units penicillin G and of 2 g of PAPM/BP for about 1 month. Double valve replacement for the aortic and mitral valves was performed 46 days after admission, when signs and symptoms of infection had improved. The operation was successful, and cardiac function was improved. Transesophageal and transthoracic echocardiography proved useful for clinical diagnosis and follow-up of endocarditis, as well as for clinical selection of surgical procedures. It is important to determine penicillin tolerance with MBC/MIC, especially when Streptococcus organisms are present.