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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 intergenic spacer (IGS) fragment generated within thisstudy and compared with IGS downloaded from GenBank. Accession nos.DQ000277–DQ000287 were determined in this study.
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Related In: Results  -  Collection


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Figure 1: Neighbor-joining phylogenetic tree (bootstrap value 250) showingclustering of intergenic spacer (IGS) fragment generated within thisstudy and compared with IGS downloaded from GenBank. Accession nos.DQ000277–DQ000287 were determined in this study.

Mentions: Cultivable isolates of B. duttonii were identical over the587-bp portion of the IGS sequenced and, consequently, the Ly strain wasselected to represent these isolates. This isolate has been used by others asrepresentative for B. duttonii (2,20). When applied toB. recurrentis, IGS fragment sequencingwas able to group these isolates into 2 types that differed by 2 nucleotides(nt). Of the 18 isolates A1–A10, A17, and A18 comprised type I, whileisolates A11–A16 gave a second type II profile. When the 2B. recurrentis types were compared withB. duttonii types I–IV, differencesappeared negligible (Table 1, Figure 1). The IGS fragment sequences ofB. duttonii type II andB. recurrentis type I were identical.


Typing African relapsing fever spirochetes.

Scott JC - Emerging Infect. Dis. (2005)

Neighbor-joining phylogenetic tree (bootstrap value 250) showingclustering of intergenic spacer (IGS) fragment generated within thisstudy and compared with IGS downloaded from GenBank. Accession nos.DQ000277–DQ000287 were determined in this study.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 1: Neighbor-joining phylogenetic tree (bootstrap value 250) showingclustering of intergenic spacer (IGS) fragment generated within thisstudy and compared with IGS downloaded from GenBank. Accession nos.DQ000277–DQ000287 were determined in this study.
Mentions: Cultivable isolates of B. duttonii were identical over the587-bp portion of the IGS sequenced and, consequently, the Ly strain wasselected to represent these isolates. This isolate has been used by others asrepresentative for B. duttonii (2,20). When applied toB. recurrentis, IGS fragment sequencingwas able to group these isolates into 2 types that differed by 2 nucleotides(nt). Of the 18 isolates A1–A10, A17, and A18 comprised type I, whileisolates A11–A16 gave a second type II profile. When the 2B. recurrentis types were compared withB. duttonii types I–IV, differencesappeared negligible (Table 1, Figure 1). The IGS fragment sequences ofB. duttonii type II andB. recurrentis type I were identical.

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