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A Case of Infective Endocarditis Caused by Gemella haemolysans
1)Department of Infectious Diseases, Ise Red Cross Hospital, 2)Department of Infection Control and Prevention, Mie University Hospital
Hirokazu TOYOSHIMA1), Hirohisa HISADA1), Shigetoshi SAKABE1), Akiko NAKAMURA2) & Masaki TANABE2)
(Received March 13, 2017)
(Accepted October 25, 2017)
Key words: Gemella haemolysans, infective endocarditis, Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS)

Gemella haemolysans are gram-variable cocci arranged in pairs, tetrads, clusters, or short chains. These bacteria are commensals of the upper respiratory, gastrointestinal and genitourinary tracts, but may also cause infections including endocarditis.

We here on report a 70-year-old female with a past history of mitral valve replacement for mitral valve stenosis who presented with several days of fever, dyspnea, left lower abdominal pain and anorexia. Chest X-ray showed congestion, and all blood cultures drawn at admission revealed gram positive cocci in clusters on day 3. Transthoracic echocardiography on day 3 revealed a mobile echogenic mass at the middle atrial site of the mitral bioprosthetic valve. As Staphylococcus aureus was initially suspected as a pathogen, vancomycin was administrated intravenously. However colony growth on blood agar medium revealed α-hemolysis and as such, the causative organism was "not identified" using conventional methods. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and partial 16S rRNA gene sequencing identified the pathogen as G. haemolysans on day 5 after admission. We thus made the diagnosis of infective endocarditis caused by G. haemolysans. As head MRI (diffusion) revealed acute phase lacunar infarction, a combination of ceftriaxone and gentamicin was administrated for 5 weeks. Her symptoms improved gradually. Finally, the vegetation disappeared on transesophageal echocardiography on day 26 after admission. Enhanced computed tomography revealed no evidence of fresh organic infarction on day 42. There has not been any recurrence of infective endocarditis and no progression of mitral regurgitation for over a year.

[ Kansenshogaku Zasshi 92: 71-75, 2018 ]

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