Borrelia isolates in Northern Colorado identified as Borrelia bissettii

Abstract

Previous work described Borrelia burgdorferi sensu lato group DN127 as a new genospecies, Borrelia bissettii, and prompted the present study to identify the Borrelia spp. that exist in northern Colorado. To determine the genospecies present, we analyzed two specific intergenic spacer regions located between the 5S and 23S and the 16S and 23S ribosomal genes. Phylogenetic analysis of the derived sequences clearly demonstrated that these isolates, originating from rodents captured in the foothills of northern Colorado, diverged from B. burgdorferi sensu stricto by 5 to 5.5% and were members of the new genospecies B. bissettii.

FIG. 1

PCR amplification of the rrl-rrs region, demonstrating a 3,500-bp amplicon for prototypical B. bissettii (strain DN127) and numerous Colorado strains, as designated. B31 = B. burgdorferi sensu stricto strain B31 (low passage).

FIG. 2

Maximum-parsimony phylogenetic tree generated using PAUP. Branches indicate the percent divergence of the rrf-rrl sequence. Italicized numbers indicate parsimony bootstrap scores for the branch. N before numbers, Neotoma mexicana; P, Peromyscus (P. maniculatus, P300 and P305; P. difficilis, P83 to P85 and P90); M, Microtus ochrogaster.