Genetic linkages in B. burgdorferi | CDC EID

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Volume 16, Number 7–July 2010
Dispatch
Geographic Differences in Genetic Locus Linkages for Borrelia burgdorferi
Bridgit Travinsky, Jonas Bunikis, and Alan G. Barbour
Author affiliation: University of California, Irvine, California, USA

Suggested citation for this article

Abstract
Borrelia burdorferi genotype in the northeastern United States is associated with Lyme borreliosis severity. Analysis of DNA sequences of the outer surface protein C gene and rrs-rrlA intergenic spacer from extracts of Ixodes spp. ticks in 3 US regions showed linkage disequilibrium between the 2 loci within a region but not consistently between regions.
Most bacterial pathogens comprise a variety of strains in various proportions. For Borrelia burgdorferi, an agent of Lyme borreliosis, strains differ in their reservoir host preferences (1), propensities to disseminate in humans (2,3), and prevalences in ticks by geographic area (4,5). Strain identification of B. burgdorferi now is predominantly based on DNA sequences of either of 2 genetic loci: 1) the plasmid-borne, highly polymorphic ospC gene, which encodes outer surface protein C (6,7), or 2) the intergenic spacer (IGS) between the rrs and rrlA rDNA, here called IGS1. Other loci for genotyping are the plasmid-borne ospA gene (7) and the rrfA-rrlB rDNA intergenic spacer, here called IGS2 (8). The apparent clonality of B. burgdorferi was justification for inferring strain identity from a single locus (9,10), but the extent of genomewide genetic exchange in this species may have been underestimated (6).

Given reports of an association between disease severity and B. burgdorferi genotype (2,3), prediction of a strain’s virulence potential from its genotype has clinical, diagnostic, and epidemiologic relevance. But is a single locus sufficient for this assessment?

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Suggested Citation for this Article
Travinsky T, Bunikis J, Barbour AG. Geographic differences in genetic locus linkages for Borrelia burgdorferi. Emerg Infect Dis [serial on the Internet]. 2010 Jul [date cited]. http://www.cdc.gov/EID/content/16/7/1147.htm