A Case of Infective Endocarditis Due to Abiotrophia defectiva, and Treatment with Ertapenem

Abstract

The most frequently reported infections due to Abiotrophia defectiva worldwide are bacteraemia and endocarditis. It is estimated that A. defectiva causes approximately 5-6% of microbiologically proven endocarditis and plays a role in the etiology of culture negative endocarditis. In this article we reported a patient with infective endocarditis (IE) due to penicillin resistant A. defectiva, which caused vegetation in the mitral valve, embolism in the spleen and successfully treated with ertapenem. A 70-year-old female patient was admitted to the emergency service with fever and abdominal pain. The patient had a pronounced widespread abdominal tenderness in the left quadrant. The body temperature was 38.9 °C, C-reactive protein (CRP) level was 12.7 mg/dl and white blood cell count was 13.3x103 mm3. The patient was hospitalized to investigate fever’s reason. It was learned in the anamnesis that she used warfarin. Considering the pre-diagnosis of urinary tract infection, empirical treatment with ceftriaxone 2x1 g/day was started. However, due to the increase in International Normalized Ratio value on the second day of ceftriaxone treatment, ertapenem 1x1 g/day was started by considering drug interaction between warfarin and ceftriaxone. Transesophageal echocardiography of the patient revealed a 1.2x1.2 cm vegetation on the posterior leaflet surface of the mitral valve, and ischemia due to embolism in the spleen was detected on abdominal computer tomography. Penicillin resistant A. defectiva grew in the blood culture. The patient was diagnosed as having IE on the seventh day of her admission. Ertapenem treatment was completed in six weeks due to the patient’s absence of fever, decreased CRP level, and the absence of A. defectiva in the seventh day control blood culture. After treatment, vegetation was not observed in the transthoracic echocardiography of the patient and no signs of ischemia was detected in the spleen. Detection of A. defectiva shaped the follow-up process of our patient by bringing the diagnosis of IE to mind. In treatment of A. defectiva-related IE, guidelines suggest long-term combination of aminoglycosides with beta-lactams or vancomycin. However, in our patient, treatment was provided by using ertapenem alone for six weeks. In addition, we believed that early diagnosis and treatment in our patient prevented serious complications.

Keywords

• abiotrophia defectiva
• infective endocarditis
• ertapenem