[Infective endocarditis--a review of 21 cases in last 10 years]

Twenty one cases of infective endocarditis in last 10 years were re-evaluated by Duke's criteria. Fourteen strains of Streptococcus viridans, 4 of Enterococcus faecalis, 1 of Haemophilus parainfluenzae were isolated from blood culture. As to the minimum inhibitory concentration (MIC) of 8 strains of Streptococci, imipenem revealed the lowest MIC value, following penicillin G, ceftriaxon not equal to ampicillin, vancomycin and gentamicin. One strain of them was penicillin-resistant (0.8 micrograms/ml). Serum inhibitory test (SIT) and serum bactericidal test (SBT) were undergone for 6 cases. The assay was efficient to determine penicillin-tolerance of causative bacterium. Vegetations were observed in 18 cases of 21 by the echo-cardiography, especially transesophageal echocardiography had better diagnostic sensitivity compared to transthoracic echocardiography. However, it took 12 weeks from the first febrile episode to achieve definite diagnosis. One of reasons to take such a long time to reach diagnosis was that major causative organism was S. sanguis, whose inflammatory reaction to the host was said to be strikingly weak.