Isolation of a Novel Orientia Species ( O. chuto sp. nov.) from a Patient Infected in Dubai
NAVAL MEDICAL RESEARCH CENTER SILVER SPRING MD RICKETTSIAL DISEASES DEPT
Pagination or Media Count:
In July 2006, an Australian tourist returning from Dubai, in the United Arab Emirates UAE, developed acute scrub typhus. Her signs and symptoms included fever, myalgia, headache, rash, and eschar. Orientia tsutsugamushi serology demonstrated a 4-fold rise in antibody titers in paired serum collections 1512 to 18,192, with the sera reacting strongest against the Gilliam strain antigen. An Orientia species was isolated by the in vitro culture of the patients acute blood taken prior to antibiotic treatment. The gene sequencing of the 16S rRNA gene rrs, partial 56-kDa gene, and the full open reading frame 47-kDa gene was performed, and comparisons of this new Orientia sp. isolate to previously characterized strains demonstrated significant sequence diversity. The closest homology to the rrs sequence of the new Orientia sp. isolate was with three strains of 0. tsutsugamushi Ikeda, Kato, and Karp, with a nucleotide sequence similarity of 98.5. The closest homology to the 47-kDa gene sequence was wilh 0. tsutsugamushi strain Gilliam, with a nucleotide similarity of82.3, while the closest homology to the 56-kDa gene sequence was with 0. tsutsugamushi strain TA686, with a nucleotide similarity of 53.1 . The molecular divergence and geographically unique origin lead us to believe that this organism should be considered a novel species. Therefore, we have proposed the name Orientia chuto, and the prototype strain of this species is strain Dubai, named after the location in which the patient was infected.
- Medicine and Medical Research