PROPOSALS TO UNIFY THE GENERA GRAHAMELLA AND BARTONELLA, WITH DESCRIPTIONS OF BARTONELLA-TALPAE COMB-NOV, BARTONELLA-PEROMYSCI COMB-NOV, AND 3 NEW SPECIES, BARTONELLA-GRAHAMII SP-NOV, BARTONELLA-TAYLORII SP-NOV, AND BARTONELLA-DOSHIAE SP-NOV

Polyphasic methods were used to examine the taxonomic positions of thr ee newly identified Grahamella species. A comparison of the 16S rRNA g ene sequences of these organisms with the sequences available for othe r bacteria revealed that these three species form a tight monophyletic cluster with members of the genus Bartonella. This cluster is only re motely related to other members of the order Rickettsiales. Determinat ions of the levels of DNA relatedness between Grahamella species and B artonella species (by using a modified hydroxyapatite method) revealed that all of the species belonging to these two genera are distinct bu t closely related. On the basis of these data and the results of guani ne-plus-cytosine content and phenotypic characterization studies, we p ropose that the genera Grahamella and Bartonella should be unified and that the latter name should be retained. Bartonella talpae and Barton ella peromysci, new combinations for former Grahamella species, are cr eated, and the following three new Bartonella species are described: B artonella grahamii, Bartonella taylorii, and Bartonella doshiae. A tax onomic analysis of Grahamella species complete the study of all member s of the family Bartonellaceae, and the results of this study support the proposal that the family should be transferred out of the order Ri ckettsiales.