中耳炎の起炎菌と判明したCorynebacterium pseudodiphtheriticum

Corynebacterium Pseudodiphtheriticum as a Pathogen of Otitis Media

　はじめに

　Corynebacterium pseudodiphtherticum （以下，C．pseudodiphtheriticum）はグラム陽性桿菌で，皮膚や粘膜を初め，生体各所に存在する常在菌である。耳漏からもCorynebacterium属が検出されることは少なくなく，検出されても常在菌の汚染と考えていた。最近，当院検査部から，耳漏検体からの本菌が起炎菌であるという連絡を受け，改めて本菌の感染状況を調べてみた。314株中4株のC．pseudodiphtheriticumが中耳炎の起炎菌と判明した。本菌による感染症の報告では，多くは基礎疾患を有した患者に発症した肺炎の報告を見るが，中耳炎は国内外でも水野ら^1）の報告1例のみであった。本菌の同定法と臨床像を呈示し，今後の課題を考えた。

Corynebacterium pseudodiphtheriticum (C. pseudodiphtheriticum), a gram-positive bacillus, is well known to be the normal flora of human mucosa and skin. We described the microbiologic and clini-cal features of 4 patients from whose otorrhea C. pseudodiphtheriticum was isolated. Gram staining of otorrhea smears showed phagocytosis of C. pseudodiphtheriticum by neutrophils. Four patients with chronic otitis media had suffered from repeated otorrhea. They had taken no steroids or immuno-suppressive agents. It was suggested that an local immunocompromised condition in the middle ear due to repeated infections may promote C. pseudo-diphtheriticum infection. Gram staining of smears gives the most valuable information to detect C. pseudodiphtheriticum infection as a pathogen of otitis media.