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Typing African relapsing fever spirochetes.

Scott JC - Emerging Infect. Dis. (2005)

Bottom Line: IGS typing was unable to discriminate between the tick- and louseborne forms of disease.B. crocidurae, also present in Africa, was clearly resolved from the B. recurrentis/B. duttonii complex.Clinical significance of this spirochete is undetermined.

View Article: PubMed Central - PubMed

Affiliation: Department of Cellular and Molecular Biology, Imperial College of Science, Technology and Medicine, South Kensington, London, United Kingdom.

ABSTRACT
Relapsing fever Borrelia spp. challenge microbiologic typing because they possess segmented genomes that maintain essential genes on large linear plasmids. Antigenic variation further complicates typing. Intergenic spacer (IGS, between 16S-23S genes) heterogeneity provides resolution among Lyme disease-associated and some relapsing fever spirochetes. We used an IGS fragment for typing East African relapsing fever Borrelia spp. Borrelia recurrentis and their louse vectors showed 2 sequence types, while 4 B. duttonii and their tick vectors had 4 types. IGS typing was unable to discriminate between the tick- and louseborne forms of disease. B. crocidurae, also present in Africa, was clearly resolved from the B. recurrentis/B. duttonii complex. IGS analysis of ticks showed relapsing fever Borrelia spp. and a unique clade, distant from those associated with relapsing fever, possibly equivalent to a novel species in ticks from this region. Clinical significance of this spirochete is undetermined.

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Related in: MedlinePlus

Neighbor-joining phylogenetic tree (bootstrap value 250) showingclustering of the rrs gene between Borrelia duttonii/B. recurrentis andB. crocidurae.
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Figure 2: Neighbor-joining phylogenetic tree (bootstrap value 250) showingclustering of the rrs gene between Borrelia duttonii/B. recurrentis andB. crocidurae.

Mentions: A comparison of rrs gene sequences confirmed the differencebetween the 2 groups of B. recurrentis, inthis case, with only a single nucleotide difference (Table 2, Figure 2).Whereas the IGS fragment analysis produced different profiles within species,analysis of the rrs gene sequences, with the exception of theB. recurrentis types, produced singleclusters for each relapsing fever species (Table2, Figure 2). Differencesbetween species were small, with a 4-nt difference between B.recurrentis and B.duttonii; a 6-nt difference between B.recurrentis and B. crocidurae; and only 2nt differentiating B. duttonii andB. crocidurae (Table 2).


Typing African relapsing fever spirochetes.

Scott JC - Emerging Infect. Dis. (2005)

Neighbor-joining phylogenetic tree (bootstrap value 250) showingclustering of the rrs gene between Borrelia duttonii/B. recurrentis andB. crocidurae.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3367362&req=5

Figure 2: Neighbor-joining phylogenetic tree (bootstrap value 250) showingclustering of the rrs gene between Borrelia duttonii/B. recurrentis andB. crocidurae.
Mentions: A comparison of rrs gene sequences confirmed the differencebetween the 2 groups of B. recurrentis, inthis case, with only a single nucleotide difference (Table 2, Figure 2).Whereas the IGS fragment analysis produced different profiles within species,analysis of the rrs gene sequences, with the exception of theB. recurrentis types, produced singleclusters for each relapsing fever species (Table2, Figure 2). Differencesbetween species were small, with a 4-nt difference between B.recurrentis and B.duttonii; a 6-nt difference between B.recurrentis and B. crocidurae; and only 2nt differentiating B. duttonii andB. crocidurae (Table 2).

Bottom Line: IGS typing was unable to discriminate between the tick- and louseborne forms of disease.B. crocidurae, also present in Africa, was clearly resolved from the B. recurrentis/B. duttonii complex.Clinical significance of this spirochete is undetermined.

View Article: PubMed Central - PubMed

Affiliation: Department of Cellular and Molecular Biology, Imperial College of Science, Technology and Medicine, South Kensington, London, United Kingdom.

ABSTRACT
Relapsing fever Borrelia spp. challenge microbiologic typing because they possess segmented genomes that maintain essential genes on large linear plasmids. Antigenic variation further complicates typing. Intergenic spacer (IGS, between 16S-23S genes) heterogeneity provides resolution among Lyme disease-associated and some relapsing fever spirochetes. We used an IGS fragment for typing East African relapsing fever Borrelia spp. Borrelia recurrentis and their louse vectors showed 2 sequence types, while 4 B. duttonii and their tick vectors had 4 types. IGS typing was unable to discriminate between the tick- and louseborne forms of disease. B. crocidurae, also present in Africa, was clearly resolved from the B. recurrentis/B. duttonii complex. IGS analysis of ticks showed relapsing fever Borrelia spp. and a unique clade, distant from those associated with relapsing fever, possibly equivalent to a novel species in ticks from this region. Clinical significance of this spirochete is undetermined.

Show MeSH
Related in: MedlinePlus