NCIt definition : 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 tick hosts, Dermacentor variabilis and Dermacentor andersoni. R. rickettsii
is a pathogen that causes Rocky Mountain spotted fever.;
Alternative definition : CDISC: Any bacterial organism that can be assigned to the species Rickettsia rickettsii.;