一株小白鼠血源病原菌的分离、鉴定及生物学特性研究

Isolation,Identification and Biological Characteristics Research of a Pathogen from the Blood of Mouse

[目的]弄清一株血液征状与鼠巴尔通氏体病相似的小鼠血源细菌的分类学地位及其与鼠巴尔通氏体的区别。[方法]通过细菌常规鉴定及16S rRNA基因系统发育进化分析,对其进行了分类鉴定。利用免疫荧光和透射电镜观察、人工感染及免疫保护等试验,对该菌生物学特性进行研究。[结果]常规分类鉴定显示分离到的细菌与丹毒科丹毒属细菌靠近,但其培养、染色及生化特性与该属的猪丹毒杆菌有较大差异。16S rRNA基因序列与猪红斑丹毒丝菌相似性达98.4%,系统进化树分析该菌与猪红斑丹毒丝菌亲源关系最近。免疫荧光和透射电镜观察结果表明该菌寄生在红细胞内部,但红细胞表面分泌有该细菌抗原成分。该细菌可通过尾静脉注射、腹腔注射、口腔感染及接触感染致死小白鼠。[结论]建议将该细菌归为BⅩⅢ门(Firmicutes)Ⅱ纲(Mollicutes)Ⅴ目(未定)Ⅰ科(Erysipelotrichace-ae)Ⅰ属(Erysipelothrix)的一新种(Erysipelothrix muris sp.nov)。

[ Objective ] The research aimed to study the taxonomic status of a strain of bacterium from the mouse blood with the similar blood symptom with Haemobartonella muris disease and its difference with Haemobartonella muris. [ Method] Through conventional bacteria identifica- tion and 16S rRNA sequence analysis of phylogenetic evolution, the bacterium was classified and identified. Through the test of immunofluores- cence assay, transmission electron microscopy （TEM） and artificial infection, immune protection, the biological characteristics of the bacteria were studied. [ Result ] The conventional taxonomic identification indicated that the taxonomic placement of the bacteria was near to Erysipelothrix hu- siopathiae ,but its culture, staining, biochemical characteristics had greater difference with Erysipelothrix rhusiopathiae. Its similarity of 16S rRNA gene sequence with Erysipelothrix rhusiopathiae reached 98.4% and the phylogenetic analysis showed that the bacteria had the closest relationship with Erysipelothrix rhusiopathiae. The immunofluorescence and TEM observation results showed that the bacteria was parasitized inside the erythro- cyte. ,while there were much antigen components of the bacteria secreted on the erythrocyte surface. The bacteria was lethal to mouse by the tail vein injection,intraperitoneal injection, oral infection,contact infection： [ Conclusion] It was suggested that that this strain was classified as the new species, belonging to Phylum B XⅢ （ Firmicutes）, Class]I（ Mollicutes ）, Order V （ incertae sedis）, FamilyI （ Erysipelotrichaceae ）, Genus I（ Ery- sipelothrix ） , named as Erysipelothrix muris sp. nov.