The etiologic agent of murine typhus (see TYPHUS, ENDEMIC FLEA-BORNE).
Any bacterial organism that can be assigned to the species Rickettsia typhi.
A species of aerobic, Gram negative, rod and cocci shaped bacteria assigned to the phylum Proteobacteria. This species is obligately intracellular, motile and transmitted to humans by a tick or flea host. R. typhi is a pathogen that causes murine typhus.