rRNA Intergenic Spacer Regions for Phylogenetic Analysis of Rickettsia Species
Species of the genus Rickettsia are responsible for several human diseases, namely epidemic typhus, Rocky Mountain spotted fever, and tick-borne typhus transmitted by arthropod vectors. The rrl-rrf intergenic spacer region (rrl-rrf ITS) was sequenced for 12 Rickettsia strains, including R. typhi, 6 untested species, R. aeschlimannii, Bar29, R. helvetica, R. honei, R. massilae, and R. slovaca as well as 5 Portuguese isolates. Phylogenetic trees inferred from rrl-rrf spacer sequences using maximum-parsimony and distance methods provided largely congruent tree topologies, supported by significant bootstrap values, enabling the identification of five distinct rickettsiae clusters.
rickettsia rrl-rrf spacer phylogeny