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  • 1
    In: Infection and Immunity, 2002, Vol. 70(3), p.1367
    Description: Haemophilus ducreyi produces a periplasmic copper-zinc superoxide dismutase (Cu-Zn SOD), which is thought to protect the organism from exogenous reactive oxygen species generated by neutrophils during an inflammatory response. We had previously identified the gene, sodC, responsible for the production and secretion of Cu-Zn SOD and constructed an isogenic H. ducreyi strain with a mutation in the sodC gene (35000HP-sodC-cat). Compared to the parent, the mutant does not survive in the presence of exogenous superoxide (L. R. San Mateo, M. Hobbs, and T. H. Kawula, Mol. Microbiol. 27:391-404, 1998) and is impaired in the swine model of H. ducreyi infection (L. R. San Mateo, K. L. Toffer, P. E. Orndorff, and T. H. Kawula, Infect. Immun. 67:5345-5351, 1999). To test whether Cu-Zn SOD is important for bacterial survival in vivo, six human volunteers were experimentally infected with 35000HP and 35000HP- sodC-cat and observed for papule and pustule formation. Papules developed at similar rates at sites inoculated with the mutant or parent. The pustule formation rates were 75% (95% confidence intervals [CI], 43 to 95%) at 12 parent-inoculated sites and 67% (95% CI, 41 to 88%) at 18 mutant-inoculated sites (P = 0.47). There was no significant difference in levels of H. ducreyi recovery from mutant- and parent-inoculated biopsy sites. These results suggest that expression of Cu-Zn SOD does not play a major role in the survival of this pathogen in the initial stages of experimental infection of humans.
    Keywords: Mutants ; Virulence ; Inflammation ; Leukocytes (Neutrophilic) ; Reactive Oxygen Species ; Superoxide Dismutase ; Mutants ; Virulence ; Inflammation ; Leukocytes (Neutrophilic) ; Reactive Oxygen Species ; Superoxide Dismutase ; Bacterial Genetics ; Human Bacteriology: Others ; Papules ; Pustules ; Man ; Papules ; Pustules ; Man ; Man ; Papules ; Pustules;
    ISSN: 0019-9567
    ISSN: 00199567
    E-ISSN: 10985522
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  • 2
    In: Infection and Immunity, 2001, Vol. 69(3), p.1488
    Description: Haemophilus ducreyi produces an outer membrane protein called DsrA, which is required for serum resistance. An isogenic dsrA mutant, FX517, was constructed previously in H. ducreyi 35000. Compared to its parent, FX517 cannot survive in normal human serum. When complemented in trans with a plasmid containing dsrA, FX517 is converted to a serum-resistant phenotype (C. Elkins, K. J. Morrow, Jr., and B. Olsen, Infect. Immun. 68:1608-1619, 2000). To test whether dsrA was transcribed in vivo, we successfully amplified transcripts in five biopsies obtained from four experimentally infected human subjects. To test whether DsrA was required for virulence, six volunteers were experimentally infected with 35000 and FX517 and observed for papule and pustule formation. Each subject was inoculated with two doses (70 to 80 CFU) of live 35000 and 1 dose of heat-killed bacteria on one arm and with three doses (ranging from 35 to 800 CFU) of live FX517 on the other arm. Papules developed at similar rates at sites inoculated with the mutant or parent. However, mutant papule surface areas were significantly smaller than parent papules. The pustule formation rate was 58% (95% confidence interval [CI] of 28 to 85%) at 12 parent sites, and 0% (95% CI of 0 to 15%) at 18 mutant sites (P = 0.0004). Although biosafety regulations precluded our testing the complemented mutant in humans, these results suggest that expression of DsrA facilitates the ability of H. ducreyi to progress to the pustular stage of disease.
    Keywords: Mutation ; Bacterial Outer Membrane Proteins -- Genetics ; Chancroid -- Etiology ; Haemophilus Ducreyi -- Pathogenicity;
    ISSN: 0019-9567
    ISSN: 00199567
    E-ISSN: 10985522
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  • 3
    In: Infection and Immunity, 2003, Vol. 71(11), p.6658
    Description: With human volunteers inoculated at two sites with Haemophilus ducreyi, outcomes for a subject were not independent. In a reinfection trial, 2 of 11 previous pustule formers and 6 of 10 previous resolvers resolved all sites of infection. There was no correlation between serum bactericidal or phagocytic activity and outcome in the trial. These data indicate that different hosts are differentially susceptible to disease progression versus resolution in the model.
    Keywords: Haemophilus Ducreyi ; Infection ; Host-Pathogen Interactions ; Pathogenesis ; Models ; Microflora ; Case Reports ; Case Reports;
    ISSN: 0019-9567
    ISSN: 00199567
    E-ISSN: 10985522
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  • 4
    In: Sexually Transmitted Diseases, 2002, Vol.29(2), pp.114-118
    Description: BACKGROUND : Naturally occurring chancroid is usually more prevalent in men than in women. GOAL : To examine whether there were gender differences in susceptibility to Haemophilus ducreyi infection by analyzing the papule and pustule formation rates for men and women who were experimentally inoculated with Haemophilus ducreyi. STUDY DESIGN : Ninety volunteers were included in the analysis. A total of 189 sites were available for estimation of the papule formation rate, and 166 sites for estimation of the pustule formation rates using logistic regression modeling. RESULTS : Although there were no gender differences in papule formation rates, the women had significantly lower rates of pustule formation than the men after adjustment for the estimated delivered dose. CONCLUSIONS : In women the disease will resolve and not progress to the pustular stage of disease as often as in men. The high male-to-female ratio in naturally occurring chancroid may in part reflect biological differences in gender susceptibility to disease progression, although the mechanisms responsible for this difference are unclear.
    Keywords: Chancroid -- Demographic Aspects ; Disease Sex Factors -- Research ; Disease Susceptibility -- Demographic Aspects;
    ISSN: 0148-5717
    E-ISSN: 15374521
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  • 5
    Language: English
    In: Microbes and infection, September 2002, Vol.4(11), pp.1141-8
    Description: Haemophilus ducreyi is the causative agent of the genital ulcer disease chancroid. Chancroid is common in developing countries and facilitates human immunodeficiency virus transmission. In this review, the clinical features, epidemiology, and prospects for disease control are discussed in the context of experimental and natural infection of humans.
    Keywords: Chancroid ; Haemophilus Ducreyi
    ISSN: 1286-4579
    E-ISSN: 1769714X
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