Abstract
The genus Borrelia, originally described by Swellengrebel in 1907, contains tick- or louse-transmitted spirochetes belonging to the relapsing fever (RF) group of spirochetes, the Lyme borreliosis (LB) group of spirochetes and spirochetes that form intermittent clades. In 2014 it was proposed that the genus Borrelia should be separated into two genera; Borrelia Swellengrebel 1907 emend. Adeolu and Gupta 2014 containing RF spirochetes and Borreliella Adeolu and Gupta 2014 containing LB group of spirochetes. In this study we conducted an analysis based on a method that is suitable for bacterial genus demarcation, the percentage of conserved proteins (POCP). We included RF group species, LB group species and two species belonging to intermittent clades, Borrelia turcica Güner et al. 2004 and Candidatus Borrelia tachyglossi Loh et al. 2017. These analyses convincingly showed that all groups of spirochetes belong into one genus and we propose to emend, and re-unite all groups in, the genus Borrelia.
Highlights
The spirochete genus Borrelia, named after the French biologist Amedee Borrel, was originally described in 1907 by Swellengrebel [1], with B. anserina (Sakharoff 1891) Bergey et al 1925 designated as the type species
Our analyses indicate that insufficient genomic divergence exist between Lyme borreliosis (LB) and relapsing fever (RF) Borrelia to consider them separate genera, and that Borrelia CSIs are limited in their ability to unambiguously distinguish the taxonomic identity of B. turcica and ‘Candidatus Borrelia tachyglossi’
In order to accurately assess Borrelia intra-genus percentage of conserved proteins (POCP), the proteomes of 30 Borrelia species strains, including n = 17 strains from the LB group, n = 11 from the RF group, and n = 2 from the reptile and echidna-associated group, were retrieved from GenBank (National Center for Biotechnology Information (NCBI), Bethesda (MD), https://www.ncbi.nlm.nih.gov/) or sequenced and assembled from low passage type cultures except ‘Candidatus B. tachyglossi’ which was sequenced from a single tick [12, 19]
Summary
The spirochete genus Borrelia, named after the French biologist Amedee Borrel, was originally described in 1907 by Swellengrebel [1], with B. anserina (Sakharoff 1891) Bergey et al 1925 designated as the type species. Since numerous species and strains have been described, and members of this genus are well recognized as the aetiological agents of Lyme borreliosis (LB) and relapsing fever (RF) in humans. Lyme borreliosis and RF genospecies have long been recognized to have different clinical, biological, and epidemiological characteristics, and phylogenetic data is concordant with this, demonstrating that these two groups are genetically similar yet distinct, and form independent monophyletic sister clades that share a common ancestor [2]. LB and RF Borrelia share a common set of genetic and biological characteristics that unify these organisms as a group compared to other related spirochetes. Various vector associations of Borrelia have been found in nature, with the genus Ixodes mainly vectoring LB species while argasid ticks often vector the RF group. Some members of the RF group are associated with hard ticks
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
