裸鼠过度角化症牛棒状杆菌的分离鉴定

Isolation and identification of Corynebacterium bovis of hyperkeratosis in athymic nude mice

2010年8月一批进口入境的裸鼠在隔离期间发生了疑似国外文献报道的过度角化性皮炎,为了确诊该病及鉴定该病的病原,本研究从患病裸鼠皮肤组织分离到一株革兰氏阳性杆菌。细菌纯化后经Biolog自动生物鉴定仪系统初步鉴定为牛棒状杆菌(C.bovis);提取细菌基因组,PCR扩增16S rRNA基因,测序结果经比对与GenBank中的C.bovis同源性在99%以上;培养物感染裸鼠没有出现临床症状,但组织学检查显示,感染裸鼠表皮棘皮层增厚,表现出轻微的C.bovis感染特有的棘皮症。由此可以确认这次入境裸鼠暴发的疫病为过度角化症,病原为C.bovis。本研究首次报道了在我国实验动物设施暴发的裸鼠过度角化症,提示裸鼠感染C.bovis导致的过度角化症是实验动物质量监测中不可忽视的传染病。

An outbreak of hyperkeratosis occurred in a batch of import athymic nude mice in a laboratory animal facility during quarantine period. A bacterium was isolated from the affected animals and the isolate was identificated as Corynebacterium bovis using Biolog Microbial Identification System and confirmed by the 16S rRNA gene sequencing. The 16S rRNA gene sequence of the isolate showed over 99% homology with the sequences of C. bovis reference strains in GenBank. Animal experimental infection also demonstated that the isolate was able to induced the histopathological lesion of mild acanthosis with increased thickness of the epidermis in the skin tissue of the infected mouse, but did not develop any clinical sign of hyperkeratosis. In conclusion, the outbreak disease of hyperkeratosis in the nude mice was caused by C. boris infection. Our study for the first time provided the evidence that the outbreak of hyperkeratosis occurred in nude mice in China and indicated hyperkeratosis due to infection of C. bovis might be a important disease in quality control of laboratory animal.