卫生部微生物室间质评1012菌的鉴定与放线菌属的系统发生分析

摘要

目的 对卫生部临床检验中心2010年微生物室间质评1012菌进行鉴定，研究1012菌的分类学位置及放线菌属的系统分类现状。方法采用传统的细菌学形态检查、商品化的API、以及16S rRNA基因测序等多种手段对1012菌进行系统的鉴定。结合远程计算机系统提供的原核生物信息，构建放线菌属及相关细菌的16S rRNA基因的系统发生树，研究放线菌属的系统进化及1012菌与相关菌种之间的亲缘关系。结果1012菌为兼性厌氧、不形成芽胞的革兰氏阳性棒状菌，60多项生化实验，除L-阿拉伯糖发酵实验阴性，其余与图列茨放线菌一致。16S rRNA基因序列分析结果显示：1012菌与图列茨放线菌的同源性高达99.8％，但与放线菌属的模式菌种——牛放线菌的同源性仅为90.6％。进一步的系统发生树亦表明，放线菌科的五个菌属清晰地聚类成9个“基因属”，小弯杆菌、动弯杆菌、放线杆菌、隐秘杆菌4个菌属分别包含单一的基因群，而放线菌属则包含了5个独立的基因群。结论1012菌可鉴定为图列放线菌，但从基因的角度上分析，当前的放线菌属的组成结构过于松散，可能会重新分类。%Objectives To identified the strain 1012 from the National Center of Clinical Laboratory of China for microbe inter-laboratory quality assessment in 2010, and study the taxonomic status of strain 1012 and related species in the genus Actinomyces. Methods The bacterial traditional morphological characteristics, commercial API systems, and 16S rRNA gene sequence analysis were applied to identify the problematic culture of strain 1012. The phylogenetic tree based on the remote information of the prokaryotes systems was constructed to study the taxonomic status and evolutionary relationship of the genus Actinomyces and related species in the family Actinomycetaceae. Results Strain 1012 was determined as a kind of facuhative anaerobic, non-spot-forming, Gram-positive coryneform bacteria, which was identified to Actinomyces turicensis for the phenotypic biochemical characteristics of more than 60 items, The comparative study of 16S rRNA gene showed the strain 1012 with 99. 8％ similarities to Actinomyces turicensis, but only 90. 6％ to the type species of Actinomyces bovis in the genus Actinomyces. However, the comparative study of 16S rRNA gene showed the strain 1012 with only 90. 6％ homology to the type species of Actinomyces bovis in the genus Actinomyces. Further phylogenetic analysis showed that nine independent clusters were grouped in the family Actinomycetaceae, of which four clusters were separately represented the genera Varibaculum,Mobiluncus, Actinobaculum and Arcanobacterium, while other five clusters all were designated to the genus Actinomyces. The study showed strain 1012 was located in genus Ⅲ of Actinomyces, yet with a relatively long genetic distance to Actinomyces bovis. Conclusion The genus Actinomyces may be reclassified as one genus Actinomyces sensu stricto and several new genera for the genotypic characteristics.