nfective endocarditis (IE) caused by Staphylococcus aureus (S. aureus) is a serious septic disease that can be fatal unless effective therapy under correct diagnosis is initiated as soon as possible. 1 Although diagnostic and therapeutic methods have improved and developed, the mortality rate for S. aureus IE is still higher than that caused by other pathogens. 2 In addition, the prevalence of S. aureus IE is also becoming higher in Japan, 3,4 concurrent with an increase in predisposing factors such as use of intravascular devices and intravenous drugs. 1 Here we report recent 3 cases of S. aureus IE that had a rapidly progressive fatal clinical course despite intensive antimicrobial therapy. One patient had a prosthetic mitral valve, which was infected with methicillin-sensitive S. aureus (MSSA), and the other 2 patients were infected with methicillin-resistant S. aureus (MRSA) on native valves. We review these cases and discuss the management of S. aureus IE in relation to current studies.
Case Reports
Case 1A 64-year-old man, who had undergone replacement of a mechanical mitral valve 12 years ago in the USA, felt a general malaise and developed a high fever (>38°C) 3 days prior to admission to a community hospital where he was treated with intravenous flomoxef (2 g/day) followed by ampicillin (4 g/day). Transthoracic echocardiography on the second day revealed no definite vegetation or valve dysfunction. The high fever continued and on the third day of the clinical course, Osler's nodes appeared. He was thus strongly suspected of having IE and was transferred to the Cardiology Department for further examination and treatment. On admission, the patient was alert, with a temperature of 40.6°C, blood pressure of 120/60 mmHg, and pulse rate of 120 beats/min (irregular). Auscultation of the chest showed a grade II/VI holo-systolic murmur that was maximal at the cardiac apex and there were normal vesicular respiratory sounds without rales. The chest X-ray revealed cardiomegaly (cardiothoracic ratio 66%) without lung congestion. Electrocardiography (ECG) showed atrial fibrillation with tachycardia. Major blood chemistry findings were: hemoglobin 13.3 g/dl, white blood cell 13,000 /mm 3 , platelets 48,000 /mm 3 , C-reactive protein (CRP) 16.11 mg/dl, INR 2.38, albumin 2.9 g/dl, total bilirubin 1.1 mg/dl, LDH 467 U/L, BUN 13 mg/dl, creatinine 0.9 mg/dl, Na 132 mmol/L, K 3.9 mmol/L, and brain natriuretic peptide 230 pg/ml. Transthoracic and transesophageal echocardiography revealed a vegetation of 10 mm in length on the prosthetic mitral valve, with a mild perivalvular leak. The diagnosis of IE was made. Relatively deep wounds in both hands because of enthusiastic golf practice a few months before the onset of the sickness were suggestive as the portal of entry of the microorganism. Because the antibiotics he had been administered at the previous hospital had been ineffective, we scheduled blood culture for the following day under antibiotic-free conditions and planned to start antibiotic treatment thereafter. That nig...