Parvimonas micraによる僧帽弁感染性心内膜炎

Mitral Valve Infective Endocarditis Caused by Parvimonas Micra

Parvimonas micra（P. micra）はGram陽性嫌気性菌で，人工弁感染，歯科治療感染，敗血症性関節炎，泌尿生殖器感染などの感染例が報告されている1）．また，近年ではP. micraは大腸癌の糞便バイオマーカーとして認知されている2，3）．P. micraによる感染性心内膜炎（IE）はまれ4）で，大腸癌から腹腔内膿瘍およびP. micraによるIEを発症し，緊急手術で救命しえた症例を経験したので報告する．

We encountered a rare case of infective endocarditis caused by a common Gram-positive anaerobic coccus Parvimonas micra, originating from colorectal cancer. The patient was a 78-year-old female, presented with fever, speech disorder, and right hemiplegia resulting from stroke. Transthoracic echocardiography revealed mitral regurgitation and a mobile vegetation on the mitral valve. Computed tomography （CT） of the abdomen revealed a mass lesion or abscess in the abdomen that was highly suggestive of relevance with infective endocarditis. An urgent surgery was initially performed to prevent further cerebral infarction, with abdominal surgery planned as the second stage. During the cardiac surgery, we observed a large defect following the partial resection of an infected posterior leaflet, and the adjacent calcified annulus was repaired using autologous pericardium. This effectively controlled mitral regurgitation. Both blood cultures yielded Parvimonas micra, which has recently become known as a biomarker for colorectal cancer. Subsequently, the patient’s colorectal cancer was excised. Following the surgery, the patient was free from infection and underwent a rehabilitation program.