Molecular Phylogenetic Analysis of Non-Sexually Transmitted Strains of Haemophilus ducreyi
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Author(s)
Gaston, Jordan R.
Roberts, Sally A.
Humphreys, Tricia L.
Date Issued
March 16, 2015
Abstract
Haemophilus ducreyi, the etiologic agent of chancroid, has been previously reported to show genetic variance in several key virulence factors, placing strains of the bacterium into two genetically distinct classes. Recent studies done in yaws-endemic areas of the South Pacific have shown that H. ducreyi is also a major cause of cutaneous limb ulcers (CLU) that are not sexually transmitted. To genetically assess CLU strains relative to the previously described class I, class II phylogenetic hierarchy, we examined nucleotide sequence diversity at 11 H. ducreyi loci, including virulence and housekeeping genes, which encompass approximately 1% of the H. ducreyi genome. Sequences for all 11 loci indicated that strains collected from leg ulcers exhibit DNA sequences homologous to class I strains of H. ducreyi. However, sequences for 3 loci, including a hemoglobin receptor (hgbA), serum resistance protein (dsrA), and a collagen adhesin (ncaA) contained informative amounts of variation. Phylogenetic analyses suggest that these non-sexually transmitted strains of H. ducreyi comprise a sub-clonal population within class I strains of H. ducreyi. Molecular dating suggests that CLU strains are the most recently developed, having diverged approximately 0.355 million years ago, fourteen times more recently than the class I/class II divergence. The CLU strains' divergence falls after the divergence of humans from chimpanzees, making it the first known H. ducreyi divergence event directly influenced by the selective pressures accompanying human hosts.
Journal
PLoS One
Department
Biochemistry
Biology
Citation
Gaston JR, Roberts SA, Humphreys TL (2015) Molecular Phylogenetic Analysis of Non-Sexually Transmitted Strains of Haemophilus ducreyi. PLoS ONE 10(3): e0118613. doi:10.1371/journal.pone.0118613
Publisher
Public Library of Science
Version of Article
Published article
DOI
10.1371/journal.pone.0118613
ISSN
1932-6203
Rights
© 2015 Gaston et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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