Characterization of a new antigenic type, Kuroki, of Rickettsia tsutsugamushi isolated from a patient in Japan.

The Kuroki strain of Rickettsia tsutsugamushi, isolated from a patient in Kyushu, Japan, has a major, type-specific antigenic polypeptide which is distinct from the prototype strains in size (58 kilodaltons), in antigenicity, and in its cleavage pattern with N-chlorosuccinimide. These results indicate that Kuroki is another antigenic type of R. tsutsugamushi.