Phylogenetic analysis of the rompB genes of Rickettsia felis and Rickettsia prowazekii European-human and North American flying-squirrel strains

The rickettsial outer membrane protein B (rompB) gene encodes the major sur face antigens of Rickettsia species. We undertook sequencing and molecular analysis of the rompB gene of Rickettsia felis and a comparison with its ho mologs in spotted fever group (SFG) and typhus group (TG) rickettsiae, incl uding the complete sequences of two North American Eying squirrel strains a nd two European human strains of Rickettsia prowazekii. We sequenced 5,226 base pairs (bp) of the R. felis rompB, encoding a protein of 1,654 amino ac ids. We also sequenced 5,015 bp of rompB of the flying squirrel strains, en coding a protein of 1,643 amino acids. Analysis of the R. felis rompB gene sequence showed 10-13% divergence from SFG rickettsiae and 18% divergence f rom the TG rickettsiae. The rompB of all sequenced strains of R. prowazekii showed an overall similarity of 99.7-99.9%.