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  • Haemophilus Ducreyi  (2)
  • Sexually transmitted diseases
  • Virulence
  • Infection and immunity  (2)
  • 1
    Language: English
    In: Infection and immunity, May 2016, Vol.84(5), pp.1514-1525
    Description: Haemophilus ducreyi causes the sexually transmitted disease chancroid in adults and cutaneous ulcers in children. In humans, H. ducreyi resides in an abscess and must adapt to a variety of stresses. Previous studies (D. Gangaiah, M. Labandeira-Rey, X. Zhang, K. R. Fortney, S. Ellinger, B. Zwickl, B. Baker, Y. Liu, D. M. Janowicz, B. P. Katz, C. A. Brautigam, R. S. MunsonJr, E. J. Hansen, and S. M. Spinola, mBio 5:e01081-13, 2014, http://dx.doi.org/10.1128/mBio.01081-13) suggested that H. ducreyi encounters growth conditions in human lesions resembling those found in stationary phase. However, how H. ducreyi transcriptionally responds to stress during human infection is unknown. Here, we determined the H. ducreyi transcriptome in biopsy specimens of human lesions and compared it to the transcriptomes of bacteria grown to mid-log, transition, and stationary phases. Multidimensional scaling showed that the in vivo transcriptome is distinct from those of in vitro growth. Compared to the inoculum (mid-log-phase bacteria), H. ducreyi harvested from pustules differentially expressed ∼93 genes, of which 62 were upregulated. The upregulated genes encode homologs of proteins involved in nutrient transport, alternative carbon pathways (l-ascorbate utilization and metabolism), growth arrest response, heat shock response, DNA recombination, and anaerobiosis. H. ducreyi upregulated few genes (hgbA, flp-tad, and lspB-lspA2) encoding virulence determinants required for human infection. Most genes regulated by CpxRA, RpoE, Hfq, (p)ppGpp, and DksA, which control the expression of virulence determinants and adaptation to a variety of stresses, were not differentially expressed in vivo, suggesting that these systems are cycling on and off during infection. Taken together, these data suggest that the in vivo transcriptome is distinct from those of in vitro growth and that adaptation to nutrient stress and anaerobiosis is crucial for H. ducreyi survival in humans.
    Keywords: Adaptation, Physiological ; Gene Expression Profiling ; Stress, Physiological ; Carbon -- Metabolism ; Chancroid -- Microbiology ; Haemophilus Ducreyi -- Physiology
    ISSN: 00199567
    E-ISSN: 1098-5522
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  • 2
    In: Infection and Immunity, 2001, Vol. 69(6), p.4180
    Description: The lipooligosaccharide (LOS) of Haemophilus ducreyi contains a major glycoform that is immunochemically identical to paragloboside, a glycosphingolipid precursor of major human blood group antigens. We recently identified the gene responsible for the glucosyltransferase activity and constructed an isogenic mutant (35000glu-) deficient in this activity. 35000glu- makes an LOS that consists only of the heptose trisaccharide core and 2-keto-deoxyoctulosonic acid (KDO). For this study, the mutant was reconstructed in the 35000HP (human passaged [HP]) background. Five human subjects were inoculated with 35000HP and 35000HPglu- in a dose-response trial. The pustule formation rates were 40% (95% confidence interval [CI], 13.7 to 72.6%) at 10 sites for 35000HP and 46.7% (95% CI, 24.8 to 69.9%) at 15 sites for 35000HPglu-. The histopathology and recovery rates of H. ducreyi from surface cultures and biopsies obtained from mutant and parent sites were similar. These results indicate that the expression of glycoforms with sugar moieties extending beyond the heptose trisaccharide core is not required for pustule formation by H. ducreyi in humans.
    Keywords: Mutation ; Chancroid -- Physiopathology ; Glucosyltransferases -- Metabolism ; Haemophilus Ducreyi -- Pathogenicity ; Lipopolysaccharides -- Metabolism;
    ISSN: 0019-9567
    ISSN: 00199567
    E-ISSN: 10985522
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