Genetic Heterogeneity ofBorrelia burgdorferiSensu Lato in the Southern United States Based on Restriction Fragment Length Polymorphism and Sequence Analysis

Abstract

3Fifty-six strains of Borrelia burgdorferi sensu lato, isolated from ticks and vertebrate animals in Missouri, South Carolina, Georgia, Florida, and Texas, were identified and characterized by PCR-restriction fragment length polymorphism (RFLP) analysis of rrf (5S)-rrl (23S) intergenic spacer amplicons. A total of 241 to 258 bp of intergenic spacers between tandemly duplicated rrf (5S) and rrl (23S) was amplified by PCR. MseI and DraI restriction fragment polymorphisms were used to analyze these strains. PCR-RFLP analysis results indicated that the strains represented at least three genospecies and 10 different restriction patterns. Most of the strains isolated from the tick Ixodes dentatus in Missouri and Georgia belonged to the genospecies Borrelia andersonii. Excluding the I. dentatus strains, most southern strains, isolated from the ticks Ixodes scapularis and Ixodes affinis, the cotton rat (Sigmodon hispidus), and cotton mouse (Peromyscus gossypinus) in Georgia and Florida, belonged to Borrelia burgdorferi sensu stricto. Seven strains, isolated from Ixodes minor, the wood rat (Neotoma floridana), the cotton rat, and the cotton mouse in South Carolina and Florida, belonged to Borrelia bissettii. Two strains, MI-8 from Florida and TXW-1 from Texas, exhibited MseI and DraI restriction patterns different from those of previously reported genospecies. Eight Missouri tick strains (MOK-3a group) had MseI patterns similar to that of B. andersonii reference strain 21038 but had a DraI restriction site in the spacer. Strain SCGT-8a had DraI restriction patterns identical to that of strain 25015 (B. bissettii) but differed from strain 25015 in its MseI restriction pattern. Strain AI-1 had the same DraI pattern as other southern strains in the B. bissettii genospecies but had a distinct MseI profile. The taxonomic status of these atypical strains needs to be further evaluated. To clarify the taxonomic positions of these atypical Borrelia strains, the complete sequences of rrf-rrl intergenic spacers from 20 southeastern and Missouri strains were determined. The evolutionary and phylogenetic relationships of these strains were compared with those of the described genospecies in the B. burgdorferi sensu lato species complex. The 20 strains clustered into five separate lineages on the basis of sequence analysis. MI-8 and TXW-1 appeared to belong to two different undescribed genospecies, although TXW-1 was closely related to Borrelia garinii. The MOK-3a group separated into a distinct deep branch in the B. andersonii lineage. PCR-RFLP analysis results and the results of sequence analyses of the rrf-rrl intergenic spacer confirm that greater genetic heterogeneity exists among B. burgdorferi sensu lato strains isolated from the southern United States than among strains isolated from the northern United States. The B. andersonii genospecies and its MOK-3a subgroup are associated with the I. dentatus-cottontail rabbit enzootic cycle, but I. scapularis was also found to harbor a strain of this genospecies. Strains that appear to...

Genetic Diversity of the Outer Surface Protein C Gene of SouthernBorreliaIsolates and Its Possible Epidemiological, Clinical, and Pathogenetic Implications

“…Isolate MI-8 was considered an undescribed genospecies in our previous report (35), and the current ospC analysis supports this conclusion. It occupies a separate branch in both of the phylogenetic trees ( Fig.…”

“…2 and 3). Previous analyses based on rrf-rrl intergenic spacer sequences indicate the same association (35). Except for B31 which was isolated from the tick I. scapularis, all the strains in this branch of the tree were isolated from cerebrospinal fluid, blood, synovial fluid, and skin of patients in Europe (Fig.…”

The Biological Survey of Canada: A Personal History

“…Ixodes dentatus may occasionally bite humans (Hall et al 1991;Anderson et al 1996), so its potential as a vector of pathogens is of concern. It is a vector of Babesia divergens McFadyean and Stockman (Telford and Spielman 1989;Goethert and Telford 2003a), Anaplasma phagocytophilum (Goethert and Telford 2003b), and strains of Borrelia burgdorferi Oliver et al 1996;Lin et al 2001).…”

Mammal Diversity and Infection Prevalence in the Maintenance of EnzooticBorrelia burgdorferialong the Western Coastal Plains of Maryland

“…Specimen MDPl550 was identical in sequence to B. burgdorferi strain 297 within the amplified region of the flaB gene. Additionally, the specimens collected in MD were phylogenetically distinct from B. lonestari, B. bissettii and B. andersonii (Lin et al 2001, Oliver et al 2000 (Fig. 2).…”