Molecular genetic analysis and clinical characterization of Rickettsia species isolated from the Republic of Korea in 2017

Rickettsia sp. CNH17-7 was isolated from patients' blood and identified by gene analysis as a species distinct from Rickettsia japonica. In addition, similar rickettsial infection was confirmed in two species (Haemaphysalis longicornis and Ixodes nipponensis) of ticks and rodents in northeastern and southwestern provinces, Republic of Korea. Subsequently, the analysis of 16S rRNA, ompA, ompB and sca4 genes of isolate CNH17-7 revealed 100%, 99.68%, 99.57% and 99.44% sequence similarity with Rickettsia sp. HlR/D91 and Candidatus R. longicornii ROK-HL727. In this study, we report the isolation of a new Rickettsia sp. CNH17-7 and infection of different types of ticks with the same rickettsial agents.