Excerpt:

Using multilocus sequence analyses (MLSA), we investigated the phylogenetic
relationship of spirochaete strains from North America previously assigned
to the genospecies Borrelia bissettii. We amplified internal fragments of 8
housekeeping genes (clpA, clpX, nifS, pepX, pyrG, recG, rplB, and uvrA)
located on the main linear chromosome by polymerase chain reaction.
Phylogenetic analysis of concatenated sequences of the 8 loci showed that
the B. bissettii clade consisted of 4 closely related clusters which
included strains from California (including the type strain DN127-Cl9-2/p7)
and Colorado that were isolated from Ixodes pacificus, I. spinipalpis, or
infected reservoir hosts.
Several strains isolated from I. scapularis clustered distantly from B.
bissettii. Genetic distance analyses confirmed that these strains are more
distant to B. bissettii than they are to B. carolinensis, a recently
described Borrelia species, which suggests that they constitute a new
Borrelia genospecies. We propose that it be named Borrelia kurtenbachii sp.
nov. in honour of the late Klaus Kurtenbach. The data suggest that
ecological differences between B. bissettii and the new Borrelia genospecies
reflect different transmission cycles. In view of these findings, the
distinct vertebrate host-tick vector associations and the distributions of
B. bissettii and B. kurtenbachii require further investigation.