应用16SrRNA基因序列分析与细菌生化反应鉴定膝关节脓液分离的念珠状链杆菌

Identification of Streptobacillus moniliformis isolated from the knee joint pus by 16S rRNA gene sequencing and biochemical reactions

目的:对我院一名患者左膝关节脓液中分离到的1株少见病原菌进行16S rRNA基因测序鉴定,探讨该方法在临床病原菌鉴定方面的意义。方法:采用16S rRNA基因序列的测定、细菌形态学以及商品化的Vitek 2全自动细菌鉴定药敏系统、API 20NE、API 20E与API 50CH系统的生化实验进行细菌的表型鉴定。结果:该菌在血平板和巧克力平板生长缓慢,麦康凯平板不生长;血平板上菌落形态呈1~2 mm"油煎蛋"圆形凸起,边缘光滑、半透明、湿润;镜下革兰染色阴性,呈链状排列,菌体1~3μm,呈圆形、卵圆形或梭形等;Vitek 2 GN-13、API 20NE、API 20E均为不能鉴定的细菌;16S rRNA基因序列分析的结果显示该菌与念珠状链杆菌的相似度为100%。结论:该膝关节脓液分离出的病原菌为念珠状链杆菌,16S rRNA基因序列分析能提供有力的遗传学证据,结合细菌的生化反应可准确地鉴定该菌。

Objective To indentify Streptobacillus moniliformis isolated from the knee joint pus by 16S rRNA gene sequencing and biochemical reactions and explore the clinical value of the method. Methods The bacterial 16S rRNA gene sequence-based identification, bacterial morphology, VITEK 2 automate systems, API 20NE strips, API 20E strips and API 50CH were performed to identify the rare bacteria. Results The bacteria grew slow on blood agar and chocolate agar and were inhibited on Maconkey agar. The bacterial colony on blood agar tookes the form of 1 - 2 mm ＂omelette＂, which was translucent and moist with circular protrusion and smooth edges. They were Gram-staining negative and in catenation, its thalli I - 3 p^m, round, oval or fusiform. Vitek 2 GN-13, API 20NE and API 20E were unable to reach the identification of the bacteria. 16S rRNA gene sequencing showed the bacteria were similar to streptobacillus moniliformis by 100%. Conclusion The rare bacteria isolated from left knee joint are streptobacillus moniliformis. 16S rRNA gene sequences combined with the biochemical reactions is accurate in the identification of these bacteria.