Nocardia farcinicaによる脳膿瘍の2例

Two Cases of Nocardia farcinica Brain Abscess

Ⅰ．はじめに

　Nocardia症は，高齢者をはじめ後天性免疫不全症候群，臓器移植術後，造血系悪性疾患，ステロイド長期投与など免疫能の低下した患者の増加に伴い，近年増加傾向にある^4,8,19)．一方，免疫能の低下を伴わない健常成人で発症したという報告も散見される^{7,11,14,22,25)}．また，Nocardia脳膿瘍は全脳膿瘍のうち約2％と比較的稀であるが，その死亡率は他の脳膿瘍の3倍と予後不良である^12,17)．今回，比較的健常な成人に発症したNocardia farcinica（N. farcinica）による脳膿瘍の2例について，若干の文献的考察を加えて検討し報告する．

　Brain abscess caused by Nocardia is a relatively rare disease,but its prognosis is poor,with the fatality being 3 times as high as that of other types of brain abscess. Nocardiosis caused by N. farcinica has higher fatality rates than nocardiosis caused by the other bacteria of the genus Nocardia. We report two cases of brain abscess caused by N. farcinica. Case 1: 72-year-old immunocompetent man. In this case,the disease healed in response to burr hole drainage and treatment with antibiotics (pazufloxacin,ciprofloxacin). Case 2: A 78-year-old woman with a history of liver cirrhosis. This patient received burr hole drainage and treatment with multiple antibiotics (sulfamethoxazole/trimethoprim,pazufloxacin,meropenem,amikacin,minocycline,and linezolid). Her brain abscess tended to alleviate but her general condition worsened,leading to death. N. farcinica is often resistant to multiple antibiotics. For treatment of brain abscess caused by this bacterium,it is essential to perform pathogen identification and a drug sensitivity test immediately,and to select optimum antibiotics,taking into account the general condition of individual patients.