Infective Endocarditis Caused by Nutritionally Variant Streptococci

Background Infective endocarditis caused by nutritionally variant streptococci (NVS) has a higher rate of complications than endocarditis caused by other streptococci. The bacteriologic failure rate and the mortality rate are high. However, current knowledge on this disease derives from previous patient data from 1987. Recent case reports showed successful antibiotic treatment in the absence of surgery. Here, we report the clinical outcome of infective endocarditis caused by NVS in our hospital. Methods Data were collected by retrospective case note review. Results Between 1996 and 2006, there were 8 cases of NVS endocarditis: 4 patients had infection caused by Abiotrophia defectiva and 4 patients had infection caused by Granulicatella adiacens. Vegetation size on echocardiography was large (10 mm) in 7 patients, and embolization occurred in 3 patients. Patients were treated with penicillin and gentamicin initially, and 3 of them were successfully treated. The regimens were shifted to vancomycin, teicoplanin, or cefotaxime in 2 cases because of poor therapeutic responses. A total of 4 patients underwent early valve replacement successfully because of severe heart failure. Three patients underwent mitral valve repair successfully at the time of 2, 4, and 7 months after the diagnosis of endocarditis. The valve cultures at surgery were negative. There was no mortality or relapse. The bacteriologic failure rate was zero. Conclusions Antibiotic treatment with penicillin and gentamicin had a high rate of success in patients with infective endocarditis caused by NVS. Early surgical intervention should be considered in those patients with deteriorating heart failure due to valve destruction.