Genetic differentiation of Chinese isolates of Rickettsia sibirica by partial ompA gene sequencing and multispacer typing.

Current data on rickettsiae and rickettsial diseases in China remain limited. Using partial ompA gene sequencing and multispacer typing, we identified 15 rickettsial isolates from China. All isolates were found to belong to Rickettsia sibirica subsp. sibirica. Four isolates from Dermacentor sinicus collected in Beijing, China, were fully identical to strain BJ-90, previously demonstrated to belong to R. sibirica subsp. sibirica despite antigenic and genotypic specificities. All 11 remaining isolates were similar to the R. sibirica subsp. sibirica type strain, 246. These were widely distributed in China in humans and different tick species. We emphasize the importance of surveying the distribution of R. sibirica in China.