1PhD Scholar, Department of Microbiology, Sri Devaraj Urs Medical College, Kolar, Karnataka, India
2Professor and Head, Department of Microbiology, Sri Devaraj Urs Medical College, Kolar, Karnataka, India
Online published on 19 July, 2019.
O. tsutsugamushi is a causative agent of scrub typhus that is widespread in Asia-Pacific region and it shows a high degree of antigenic variation. This study was done to find the circulating genotypes of circulating genotypes of O. tsutsugamushi from patients with scrub typhus in Kolar district. A total of 197 patients with symptoms were included in the study and Scrub typhus in patients was confirmed by performing Scrub typhus IgM ELISA and Weil-Felix test. All sero-positive samples were subjected to standard PCR and DNA sequencing performed for PCR positive samples. Out of 67 seropositive samples, 22 samples were positive for OT 56kDa type specific antigen gene. Of these 22 amplified samples, 17 DNA sequences yielded good results. Phylogenetic analysis of 17 sequences showed 10 (58.8%) clustered with Karp-like strain, 6 (35.2%) with Boryang-like and one with Orientia chuto Dubai strain. This study shows there is a great genetic diversity among the O. tsutsugamushi. These circulating genotypes would be helpful in the development of vaccines and rapid diagnostic tests.
O. tsutsugamushi, Scrub typhus, 56 kDa Type specific antigen, PCR, DNA sequencing
