DOI: 10.36347/sjmcr.2015.v03i03.020

Pages: 246-248

Streptococcus mitis is the common colonized bacterium in human oral cavity, skin and gastrointestinal tract. It is an opportunistic pathogen. We report a 21-year-old Chinese man with infective endocarditis and lung abscess, who had a history of antibiotics abuse and presented as fever, cough and expectoration. Echocardiography revealed a membranous ventricular septal defect of 6mm and an excrescence of 18x6mm on the tricuspid valve which presented moderate regurgitation. 64-slice computed tomography (CT) showed flaky opacities with airbags in the left lung. Blood samples was identified as Streptococcus mitis by automated bacterial identification / susceptibility analysis system. The drug sensitivity result indicated that it could resist penicillin, tetracycline, clindamycin, cefotaxime, vancomycin and erythromycin except amoxicillin, sulbactam and cotrimoxazole. After receiving the therapy of amoxicillin sodium and sulbactam sodium for a month, the lung infection had been completely absorbed in CT images and the excrescence vanished in echocardiography, with perforation changed on the tricuspid valve. The patient received surgical treatment on moderate systemic hypothermic cardiopulmonary bypass. The patient continued to take amoxicillin sodium and sulbactam sodium for 1 week and received therapy of penicillin for 5 weeks after the surgery. We tracked him for 3 years and 10 months, no complications occurred and he recovered to normal work and life.