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Affiliation(s)
- Tahir T Mohammed
- Dermatology Unit, Department of Medicine, College of Medicine, Lagos, Nigeria
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2
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Janowicz DM, Tenner-Racz K, Racz P, Humphreys TL, Schnizlein-Bick C, Fortney KR, Zwickl B, Katz BP, Campbell JJ, Ho DD, Spinola SM. Experimental infection with Haemophilus ducreyi in persons who are infected with HIV does not cause local or augment systemic viral replication. J Infect Dis 2007; 195:1443-51. [PMID: 17436224 PMCID: PMC2571042 DOI: 10.1086/513877] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2006] [Accepted: 11/09/2006] [Indexed: 11/03/2022] Open
Abstract
We infected 11 HIV-seropositive volunteers whose CD4(+) cell counts were >350 cells/ microL (7 of whom were receiving antiretrovirals) with Haemophilus ducreyi. The papule and pustule formation rates were similar to those observed in HIV-seronegative historical control subjects. No subject experienced a sustained change in CD4(+) cell count or HIV RNA level. The cellular infiltrate in biopsy samples obtained from the HIV-seropositive and HIV-seronegative subjects did not differ with respect to the percentage of leukocytes, neutrophils, macrophages, or T cells. The CD4(+):CD8(+) cell ratio in biopsy samples from the HIV-seropositive subjects was 1:3, the inverse of the ratio seen in the HIV-seronegative subjects (P<.0001). Although CD4(+) cells proliferated in lesions, in situ hybridization and reverse-transcription polymerase chain reaction for HIV RNA was negative. We conclude that experimental infection in HIV-seropositive persons is clinically similar to infection in HIV-seronegative persons and does not cause local or augment systemic viral replication. Thus, prompt treatment of chancroid may abrogate increases in viral replication associated with natural disease.
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Affiliation(s)
- Diane M Janowicz
- Department of Medicine, Indiana University, School of Medicine, Indianapolis, IN 46202, USA.
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3
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Fulcher RA, Cole LE, Janowicz DM, Toffer KL, Fortney KR, Katz BP, Orndorff PE, Spinola SM, Kawula TH. Expression of Haemophilus ducreyi collagen binding outer membrane protein NcaA is required for virulence in swine and human challenge models of chancroid. Infect Immun 2006; 74:2651-8. [PMID: 16622201 PMCID: PMC1459755 DOI: 10.1128/iai.74.5.2651-2658.2006] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Haemophilus ducreyi, the etiologic agent of the sexually transmitted genital ulcer disease chancroid, has been shown to associate with dermal collagen fibers within infected skin lesions. Here we describe NcaA, a previously uncharacterized outer membrane protein that is important for H. ducreyi collagen binding and host colonization. An H. ducreyi strain lacking the ncaA gene was impaired in adherence to type I collagen but not fibronectin (plasma or cellular form) or heparin. The mutation had no effect on serum resistance or binding to HaCaT keratinocytes or human foreskin fibroblasts in vitro. Escherichia coli expressing H. ducreyi NcaA bound to type I collagen, demonstrating that NcaA is sufficient to confer collagen attachment. The importance of NcaA in H. ducreyi pathogenesis was assessed using both swine and human experimental models of chancroid. In the swine model, 20% of lesions from sites inoculated with the ncaA mutant were culture positive for H. ducreyi 7 days after inoculation, compared to 73% of wild-type-inoculated sites. The average number of CFU recovered from mutant-inoculated lesions was also significantly reduced compared to that recovered from wild-type-inoculated sites at both 2 and 7 days after inoculation. In the human challenge model, 8 of 30 sites inoculated with wild-type H. ducreyi progressed to the pustular stage, compared to 0 of 30 sites inoculated with the ncaA mutant. Together these results demonstrate that the collagen binding protein NcaA is required for H. ducreyi infection.
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Affiliation(s)
- Robert A Fulcher
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
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4
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Affiliation(s)
- Kabir Sardana
- Department of Dermatology and Venereology, Lady Hardinge Medical College, New Delhi, India
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5
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Humphreys TL, Baldridge LA, Billings SD, Campbell JJ, Spinola SM. Trafficking pathways and characterization of CD4 and CD8 cells recruited to the skin of humans experimentally infected with Haemophilus ducreyi. Infect Immun 2005; 73:3896-902. [PMID: 15972475 PMCID: PMC1168611 DOI: 10.1128/iai.73.7.3896-3902.2005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
T-cell homing to infected skin is not well studied in humans. We examined sites experimentally infected with Haemophilus ducreyi by immunohistochemistry and flow cytometry for expression of receptors and ligands involved in cutaneous T-cell homing and determined the phenotypes of the T cells that trafficked to skin. Endothelial cells expressed E-selectin in infected but not uninfected skin, while peripheral node addressin (PNAd) was minimally expressed in all samples. CC chemokine ligand 27 (CCL27) was expressed in the epidermis and endothelium of both infected and uninfected skin. Interestingly, CCL21, a chemokine thought to be associated principally with T-cell trafficking in the lymphatic compartment, was highly expressed on the endothelium of infected skin. Few naive cells were present in experimental lesions, emphasizing the combined role of PNAd and CCL21 in trafficking of this subset. Memory cells (CD45RA-) dominated both CD4 and CD8 T-cell populations at the site of infection. Effector memory (CD45RA- CD27-) CD4+ and CD8+ T cells were enriched in lesions. Although the CC chemokine receptor 7-positive (CCR7+) population of both central memory (CD45RA- CD27+) and effector memory cells was not enriched in the skin compared to peripheral blood, CCR7+ cells were not precluded from entering infected skin. Taken together with our previous work (D. Soler, T. L. Humphreys, S. M. Spinola, and J. J. Campbell, Blood 101:1677-1683, 2003), these studies led us to propose a model of memory T-cell trafficking to skin in response to experimental H. ducreyi infection.
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Affiliation(s)
- Tricia L Humphreys
- Department of Medicine, Indiana University, Indianapolis, Indiana 46202, USA.
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6
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Wu JJ, Huang DB, Pang KR, Tyring SK. Selected sexually transmitted diseases and their relationship to HIV. Clin Dermatol 2005; 22:499-508. [PMID: 15596321 DOI: 10.1016/j.clindermatol.2004.07.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Although sexually transmitted diseases (STDs) are underreported and underrecognized, they are a major source of morbidity, mortality, and represent a major socioeconomic cost in developing and industrialized nations. Individuals who develop STDs are often coinfected with human immunodeficiency virus (HIV). Coinfection with HIV both facilitates the natural history of STDs and worsens the clinical picture. The objective of this article is to provide a review to the practicing clinician on the epidemiology, clinical manifestations, methods of diagnosis, and treatment for four cutaneous STDs--chancroid, genital herpes, granuloma inguinale, and lymphogranuloma venereum--in coinfected HIV patients.
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Affiliation(s)
- Jashin J Wu
- Department of Dermatology, University of California College of Medicine Irvine, Irvine, California, USA
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7
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Sardana K, Sehgal VN. Genital ulcer disease and human immunodeficiency virus: a focus. Int J Dermatol 2004. [DOI: 10.1111/j.1365-4632.2004.02268.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Moodley P, Sturm PDJ, Vanmali T, Wilkinson D, Connolly C, Sturm AW. Association between HIV-1 infection, the etiology of genital ulcer disease, and response to syndromic management. Sex Transm Dis 2003; 30:241-5. [PMID: 12616144 DOI: 10.1097/00007435-200303000-00013] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Reports on the effect of HIV-1 infection on healing rates of ulcers are conflicting. GOAL The goal was to determine the etiology and response to treatment of genital ulcer disease (GUD) in relation to HIV-1 infection. STUDY DESIGN This was a cohort study of patients with GUD treated with local syndromic management protocols. RESULTS Among the 587 recruited, the prevalences of infections due to HSV, Treponema pallidum, Chlamydia trachomatis (lymphogranuloma venereum [LGV]), Haemophilus ducreyi, Calymmatobacterium granulomatis, and HIV-1 were 48%, 14%, 11%, 10%, 1%, and 75%, respectively. The prevalence T. pallidum of was higher among men (P = 0.03), and an association was seen among HIV-1-seronegatives on univariate and multivariate analyses (P < 0.001; = 0.01). The prevalence of C trachomatis (LGV) was higher among females (P = 0.004), and an association was seen among HIV-1-seropositives on univariate analysis (P = 0.04). At follow-up, 40/407 (10%) showed a decreased healing tendency, not associated with ulcer etiology or HIV-1 seropositivity. CONCLUSION Response to syndromic management of GUD was acceptable and not associated with HIV-1 coinfection.
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Affiliation(s)
- Prashini Moodley
- Africa Centre for Health and Population Studies, Nelson R. Mandela School of Medicine, University of Natal, Durban, South Africa
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9
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Affiliation(s)
- Virendra N Sehgal
- Dermato-Venereology (Skin/VD) Center, Sehgal Nursing Home, Panchwati, Azadpur, Delhi, India.
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10
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Abstract
Chancroid is a sexually transmitted disease (STD) caused by the Gram negative bacterium Haemophilus ducreyi and is characterised by necrotising genital ulceration which may be accompanied by inguinal lymphadenitis or bubo formation. H ducreyi is a fastidious organism which is difficult to culture from genital ulcer material. DNA amplification techniques have shown improved diagnostic sensitivity but are only performed in a few laboratories. The management of chancroid in the tropics tends to be undertaken in the context of syndromic management of genital ulcer disease and treatment is usually with erythromycin. A number of single dose regimens are also available to treat H ducreyi infection. Genital ulceration as a syndrome has been associated with increased transmission of human immunodeficiency virus (HIV) infection in several cross sectional and longitudinal studies. Effective and early treatment of genital ulceration is therefore an important part of any strategy to control the spread of HIV infection in tropical countries.
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Affiliation(s)
- D A Lewis
- Patrick Clements Clinic, Central Middlesex Hospital, Northwest London Hospitals NHS Trust, London NW10 7NS, UK.
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11
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Svensson LA, Henning P, Lagergård T. The cytolethal distending toxin of Haemophilus ducreyi inhibits endothelial cell proliferation. Infect Immun 2002; 70:2665-9. [PMID: 11953409 PMCID: PMC127913 DOI: 10.1128/iai.70.5.2665-2669.2002] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2001] [Revised: 11/04/2001] [Accepted: 01/29/2002] [Indexed: 11/20/2022] Open
Abstract
Haemophilus ducreyi, the etiologic agent of the sexually transmitted disease chancroid, produces a cytolethal distending toxin (HdCDT) that inhibits mammalian cell proliferation. We investigated the effects of HdCDT on normal human endothelial cells and on tubule formation in an in vitro model of angiogenesis. Endothelial cells were arrested in the G2 phase of the cell cycle, and tubule formation was inhibited in a dose-dependent manner. The antiproliferative activities of HdCDT on endothelial cells might contribute to the characteristic slow healing and persistence of chancroid ulcers.
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Affiliation(s)
- Liselott A Svensson
- Department of Medical Microbiology and Immunology, Göteborg University, S-4136 Göteborg, Sweden
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12
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Spinola SM, Bauer ME, Munson RS. Immunopathogenesis of Haemophilus ducreyi infection (chancroid). Infect Immun 2002; 70:1667-76. [PMID: 11895928 PMCID: PMC127820 DOI: 10.1128/iai.70.4.1667-1676.2002] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Affiliation(s)
- Stanley M Spinola
- Department of Medicine, School of Medicine, Indiana University, Indianapolis, Indiana 46202, USA.
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Bong CTH, Harezlak J, Katz BP, Spinola SM. Men are more susceptible than women to pustule formation in the experimental model of Haemophilus ducreyi infection. Sex Transm Dis 2002; 29:114-8. [PMID: 11818898 DOI: 10.1097/00007435-200202000-00009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
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.
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Affiliation(s)
- Cliffton T H Bong
- Department of Medicine, Indiana University, Indianapolis, Indiana, USA
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Røttingen JA, Cameron DW, Garnett GP. A systematic review of the epidemiologic interactions between classic sexually transmitted diseases and HIV: how much really is known? Sex Transm Dis 2001; 28:579-97. [PMID: 11689757 DOI: 10.1097/00007435-200110000-00005] [Citation(s) in RCA: 387] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Many studies have explored the role of "classic" sexually transmitted diseases (STDs) in determining the pattern of HIV epidemics. However, the many different STDs may contribute in different ways, at different magnitudes. GOAL To review available studies on the bidirectional interactions of HIV and STDs to explore the extent of current knowledge on the different influences of the varied STDs in heterosexual HIV epidemics. METHODS Longitudinal studies on susceptibility and controlled studies on infectiousness and duration of disease identified on electronic databases through reference lists and citation indices up to the end of 1999 were systematically reviewed, including meta-analyses assessing the influence of STDs on susceptibility to HIV. RESULTS Studies have a clear publication bias with a significant result that hinders robust interpretation. However, genital ulcerative disease appears to have a greater impact than nonulcerative disease, and men are more affected than women by the effects of STDs on susceptibility to HIV. There is evidence that STDs increase the infectiousness of HIV from men to women, whereas the evidence is more equivocal for the infectiousness of women. Few studies identify the impact of different STDs, and there is a marked lack of studies investigating the impact of HIV infection on the transmission of other STDs. CONCLUSIONS A large body of work has measured the association between STDs and HIV. However, publication bias and gaps in the focus of studies mean that a detailed, quantitative understanding of the interaction requires much more attention.
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Affiliation(s)
- J A Røttingen
- Department of Infectious Disease Epidemiology, Imperial College School of Medicine at St Mary's, London, United Kingdom.
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15
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Wood GE, Dutro SM, Totten PA. Haemophilus ducreyi inhibits phagocytosis by U-937 cells, a human macrophage-like cell line. Infect Immun 2001; 69:4726-33. [PMID: 11447144 PMCID: PMC98558 DOI: 10.1128/iai.69.8.4726-4733.2001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Haemophilus ducreyi is a gram-negative obligate human pathogen that causes the genital ulcer disease chancroid. Chancroid lesions are deep necrotic ulcers with an immune cell infiltrate that includes macrophages. Despite the presence of these phagocytic cells, chancroid ulcers can persist for months and live H. ducreyi can be isolated from these lesions. To analyze the interaction of H. ducreyi with macrophages, we investigated the ability of H. ducreyi strain 35000 to adhere to, invade, and survive within U-937 cells, a human macrophage-like cell line. We found that although H. ducreyi strain 35000 adhered efficiently to U-937 cells, few bacteria were internalized, suggesting that H. ducreyi avoids phagocytosis by human macrophages. The few bacteria that were phagocytosed in these experiments were rapidly killed. We also found that H. ducreyi inhibits the phagocytosis of a secondary target (opsonized sheep red blood cells). Antiphagocytic activity was found in logarithmic, stationary-phase, and plate-grown cultures and was associated with whole, live bacteria but not with heat-killed cultures, sonicates, or culture supernatants. Phagocytosis was significantly inhibited after a 15-min exposure to H. ducreyi, and a multiplicity of infection of approximately 1 CFU per macrophage was sufficient to cause a significant reduction in phagocytosis by U-937 cells. Finally, all of nine H. ducreyi strains tested were antiphagocytic, suggesting that this is a common virulence mechanism for this organism. This finding suggests a mechanism by which H. ducreyi avoids killing and clearance by macrophages in chancroid lesions and inguinal lymph nodes.
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Affiliation(s)
- G E Wood
- Department of Medicine, Division of Infectious Diseases, University of Washington, Seattle, Washington 98195, USA
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Gelfanova V, Humphreys TL, Spinola SM. Characterization of Haemophilus ducreyi-specific T-cell lines from lesions of experimentally infected human subjects. Infect Immun 2001; 69:4224-31. [PMID: 11401958 PMCID: PMC98455 DOI: 10.1128/iai.69.7.4224-4231.2001] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Haemophilus ducreyi is the etiologic agent of chancroid, a sexually transmitted genital ulcer disease that facilitates the transmission of human immunodeficiency virus. In the human model of infection, the histopathology of infected sites in part resembles a delayed-type hypersensitivity (DTH) response. In this study, T cells were isolated from skin biopsy specimens obtained from 24 subjects who were infected for 7 to 14 days. One clone and 12 lines that responded to H. ducreyi antigens were obtained from 12 of the subjects. Fluorescence-activated cell sorter analysis showed that the antigen-responsive lines and clone were predominantly CD3(+) and CD4(+). The lines and clone responded to H. ducreyi antigen in a dose-dependent manner and produced gamma interferon (IFN-gamma) alone or IFN-gamma and interleukin-10 (IL-10) but no IL-4 or IL-5 in response to H. ducreyi. Proliferation of T cells was dependent on the presence of autologous antigen-presenting cells. The lines showed little response to antigens prepared from other members of the Pasteurellaceae and responded to different fractions of H. ducreyi separated by preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis. We conclude that T cells that recognize H. ducreyi antigens are recruited to sites experimentally infected with the organism. The lack of cross-reactivity to the Pasteurellaceae and the response of the lines to different antigen fractions suggest that subjects are sensitized to H. ducreyi during the course of infection.
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Affiliation(s)
- V Gelfanova
- Departments of Medicine, Indiana University, Indianapolis, Indiana 46202, USA
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Young RS, Fortney KR, Gelfanova V, Phillips CL, Katz BP, Hood AF, Latimer JL, Munson RS, Hansen EJ, Spinola SM. Expression of cytolethal distending toxin and hemolysin is not required for pustule formation by Haemophilus ducreyi in human volunteers. Infect Immun 2001; 69:1938-42. [PMID: 11179379 PMCID: PMC98108 DOI: 10.1128/iai.69.3.1938-1942.2001] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Haemophilus ducreyi makes cytolethal distending toxin (CDT) and hemolysin. In a previous human challenge trial, an isogenic hemolysin-deficient mutant caused pustules with a rate similar to that of its parent. To test whether CDT was required for pustule formation, six human subjects were inoculated with a CDT mutant and parent at multiple sites. The pustule formation rates were similar at both parent and mutant sites. A CDT and hemolysin double mutant was constructed and tested in five additional subjects. The pustule formation rates were similar for the parent and double mutant. These results indicate that neither the expression of CDT, nor that of hemolysin, nor both are required for pustule formation by H. ducreyi in humans.
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Affiliation(s)
- R S Young
- Department of Medicine, School of Medicine, Indiana University, Indianapolis, Indiana 46202, USA
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Czelusta A, Yen-Moore A, Van der Straten M, Carrasco D, Tyring SK. An overview of sexually transmitted diseases. Part III. Sexually transmitted diseases in HIV-infected patients. J Am Acad Dermatol 2000; 43:409-32; quiz 433-6. [PMID: 10954653 DOI: 10.1067/mjd.2000.105158] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
UNLABELLED The HIV epidemic has dramatically altered the field of sexually transmitted diseases (STDs). HIV infection is unique among sexually transmitted diseases because it can modify the clinical presentation and features of other STDs. Conversely, other STDs can affect the transmission of HIV. This review is the third part of a series that has provided a general overview of STDs. In this article, genital ulcer diseases (genital herpes, syphilis, chancroid, lymphogranuloma venereum, and granuloma inguinale), human papillomavirus infection (anogenital warts and subclinical infections), molluscum contagiosum, human herpesvirus 8 infection, viral hepatitis, and ectoparasitic infestations (scabies and pediculosis pubis) are discussed as they occur in HIV-infected hosts. Additional features as they relate to HIV-infected patients, such as epidemiology and transmission, are discussed when applicable. LEARNING OBJECTIVE At the conclusion of this learning activity, participants should improve their understanding of sexually transmitted diseases in the HIV-infected host.
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Affiliation(s)
- A Czelusta
- Department of Dermatology at the University of Texas- Houston Health Science Center and St Joseph Hospital, Houston, USA
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19
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Affiliation(s)
- D A Lewis
- Department of Genitourinary Medicine, Imperial College School of Medicine, Paddington, London.
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Abstract
Chancroid is a sexually transmitted disease caused by the bacterium Haemophilus ducreyi. It usually presents as a genital ulcer and may be associated with regional lymphadenopathy and bubo formation. H. ducreyi infection is predominantly seen in tropical resource-poor regions of the world where it is frequently the most common etiological cause of genital ulceration. Genital ulcer disease has been shown to be an extremely important co-factor in HIV transmission. With the advent of the AIDS epidemic, there has been increased research effort to elucidate those factors involved in the pathogenesis of chancroid. Several putative virulence factors have now been identified and isogenic H. ducreyi mutants constructed by mutagenesis of their encoding genes. This approach has facilitated investigations into the role each of these putative virulence factors may play in H. ducreyi pathogenesis through the use of in vitro and in vivo model systems. One major goal of current chancroid research is to identify antigens which are immunogenic and could form the basis of a vaccine against H. ducreyi infection. Such a vaccine, if shown to be effective in decreasing the prevalence of chancroid, could have the added benefit of slowing down the HIV incidence rates in those populations where chancroid is a major co-factor for HIV transmission.
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Affiliation(s)
- D A Lewis
- Department of Microbiology, Imperial College School of Medicine, London, United Kingdom.
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