This diagram is adapted from Roux and Raoult (1), although not to scale. It shows the phylogenetic classification of the genus Rickettsia based upon sequence comparisons of rOmpB genes.  The colored boxes enclose monophyletic groups or clades within the genus, with sensitivity to erythromycin and/or rifampin being noted in this paper as clade characteristics.

For more information on the various species and products  click on the appropriate species name. Although MIF testing has been the serologic gold standard, orginally being the means of determining separate species, the main obstacle is their common  lipopolysaccharide (LPS) antigen. As all of the spotted fever group share the same LPS antigen, the effect of differences in rOmpB reactivity is diminished. Our goal is to present you with specific panels of purified rOmpB-coated wells to allow a clade-specific diagnosis.

1) Roux, V. & D. Raoult, 2000. Phylogenetic analysis of members of the genus Rickettsia using the gene encoding the outer-membrane protein rOmpB (ompB). Int. J. Syst. Evol. Microbiol. 50: 1449-1455.

Please note that Candidatus Rickettsia amblyommii is placed within the blue-outlined clade between R. montanensis and R. raoultii.