Identification of Japanese isolates of spotted fever group rickettsiae

用小鼠抗血清对日本四国县东南部病人分离的斑点热群立克次体进行了鉴定。通过计算特异性差异(SPD)来检验5株日本分离株与致病性SFG立克次体标准株的抗原性差异。日本株与SFG致病标准株的SPD有明显的差异，表明日本株与R.akari、R.australis、R.conorii、R.rickettsii和R.siBirica明显不同。日本株也不同于泰国立克次体(TT-118株)，该株仅在东方已知。日本株与标准株无交叉反应，而日本株与日本株的单抗呈阳性反应。用日本立克次体小鼠抗血清对日本株和标准株进行免疫印迹比较，结果表明日本株与标准株有所不同。本研究的结果表明，日本分离的SFG立克次体属于不同于任何已知对人类致病的SFG立克次体的单一种。我们提出了日本立克次体的分类学名称。11月与日本有关，因为日本是它第一次被孤立的国家。

Spotted fever group (SFG) rickettsiae isolated from patients in the southeastern part of Shikoku, Japan, were analyzed to identify the species by use of mouse antisera. Antigenic differences between five strains of Japanese isolates and standard strains of pathogenic SFG rickettsiae were examined by calculating the specificity difference (SPD). the SPD between each pair of Japanese strains showed their antigenic identity, while the SPD between Japanese strains and pathogenic standard strains of SFG indicated that Japanese strains are clearly distinct from R.akari, R.australis, R.conorii, R.rickettsii, and R.sibirica. It was also demonstrated that Japanese strains are different from Thai tick typhus rickettsia (strain TT-118) isolated from a tick, known only in the Orient. Monoclonal antibody analysis resulted in no cross-reaction between Japanese strain and standard strains but positive reactions of Japanese strains with monoclonal antibody to Japanese strain. Comparison of the Japanese strain and standard strains of SFG rickettsiae by Western immunoblotting with mouse antiserum to Japanese strain demonstrated that the Japanese strain are distinct from any of the standard strain of SFG rickettsiae. The results obtained in this study demonstrated that the Japanese isolates of SFG rickettsiae belong to a single species distinct from any SFG rickettsiae known to be pathogenic to humans. We proposed the taxonomic name Rickettsia japonica sp. nov. pertaining to Japan, since that is the country in which it was first isolated.