Higgins J A, Radulovic S, Schriefer M E, Azad A F
Department of Microbiology and Immunology, University of Maryland Medical School, Baltimore 21201, USA.
J Clin Microbiol. 1996 Mar;34(3):671-4. doi: 10.1128/jcm.34.3.671-674.1996.
A flea-borne rickettsia, previously referred to as ELB, has been implicated as a cause of human illness. Using sequence data obtained from a fragment of the citrate synthase gene, we compared ELB, Rickettsia australis, R. rickettsii, and R. akari with the louse-borne R. prowazekii. We tallied 24 base pair differences between ELB and R. prowazekii and 25 between R. rickettsii and R. prowazekii; there were 30 base pair differences between R. australis and R. prowazekii and 29 between R. akari and R. prowazekii. We observed 32 differences between Rickettsia typhi and ELB. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot analyses of ELB, with typing sera against R. typhi indicate that ELB surface antigens are more closely related to the flea-borne R. typhi than to the mite-borne R. akari. On the basis of the results of citrate synthase gene sequence comparisons, as well as previous comparisons with 16S rRNA and 17-kDa-protein gene segments, we found that ELB is sufficiently genetically distinct from other rickettsiae to be designated a new species, Rickettsia felis.
一种以前被称为ELB的经跳蚤传播的立克次氏体被认为是人类疾病的病因。利用从柠檬酸合酶基因片段获得的序列数据，我们将ELB、澳大利亚立克次氏体、立氏立克次氏体和阿氏立克次氏体与经虱子传播的普氏立克次氏体进行了比较。我们统计出ELB与普氏立克次氏体之间有24个碱基对差异，立氏立克次氏体与普氏立克次氏体之间有25个碱基对差异；澳大利亚立克次氏体与普氏立克次氏体之间有30个碱基对差异，阿氏立克次氏体与普氏立克次氏体之间有29个碱基对差异。我们观察到伤寒立克次氏体与ELB之间有32个差异。用抗伤寒立克次氏体的分型血清对ELB进行十二烷基硫酸钠-聚丙烯酰胺凝胶电泳和免疫印迹分析表明，ELB的表面抗原与经跳蚤传播的伤寒立克次氏体的关系比与经螨传播的阿氏立克次氏体的关系更为密切。根据柠檬酸合酶基因序列比较的结果，以及先前与16S rRNA和17-kDa蛋白基因片段的比较，我们发现ELB在遗传上与其他立克次氏体有足够的差异，应被指定为一个新物种，即猫立克次氏体。
