Rickettsia typhi str. TH1527 Genome sequencing. Rickettsia typhi str. TH1527

Rickettsia typhi strain TH1527 was isolated in April 1965 Thailand from blood of a human with murine typhus in the District Hospital in Chiang Rai Province, Thailand; This as the first case of murine typhus reported in Thailand. Patient diagnosed with bronchitis, fever of unknown origin, and no rash. Isolate passaged 9 times in embyonated chicken eggs, 6 Vero E6 tissue culture passages, and pooled from 1-3 passages in mouse L929 cells. Organism was purified from host cells by differential centrifugation and banding In Renografin density gradients and WNA was purified with Qiagen spin columns. Rickettsia. This genus, like other Rickettsial organisms such as Neorickettsia and Anaplasma, is composed of obligate intracellular bacteria. There are two groups, the spotted fever group, and the typhus group. The latter is composed of two organisms, Rickettsia prowazekii and Rickettsia typhi. The bacteria can be transmitted via an arthropod (tick, fleas, mites, and/or lice) to a host organism or maintained transstadially and transovarially in the arthropod. When pathogenic in humans, they target endothelial cells and sometimes macrophages. They attach via an adhesin, rickettsial outer membrane proteins A and/or B, and are internalized where they persist as cytoplasmically free organisms. Rickettsia typhi. This organism causes murine (endemic) typhus and is an obligate intracellular pathogen that infects both the flea vector and hosts such as humans, commonly rats, and some other mammals. It is in the typhus group along with R. prowazekii, and genomic comparisons demonstrate colinearity and similarity to the genome of that organism except for two independent inversions near the origin and terminus. In the flea vector, the bacterium penetrates the gut epithelial barrier and is found in the feces which become infective. Rickettsia typhi strain TH1527. This is the first strain isolated in Thailand from a human case of murine typhus.