Haemophilus ducreyi
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Chancroid Microchapters |
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Haemophilus ducreyi On the Web |
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American Roentgen Ray Society Images of Haemophilus ducreyi |
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 Photomicrograph of H. ducreyi
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| Haemophilus ducreyi (Neveu-Lemaire 1921) Bergey et al. 1923 |
This page is about microbiologic aspects of the organism(s). For clinical aspects of the disease, see Chancroid.
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Yazan Daaboul, M.D.; Nate Michalak, B.A.; Serge Korjian M.D.
Overview
Haemophilus ducreyi is a fastidious Gram-negative coccobacillus causing the chancroid characterized by painful sores on the genitalia.
Organism
- Haemophilus ducreyi, also known as H. ducreyi, is a fastidious, gram-negative, coccobacillus that causes the sexually transmitted disease chancroid, characterized as a genital ulcerative disease.[1]
- H. ducreyi can range from short to relatively long bacilli with rounded ends, and typically grow in chains.
- H. ducreyi was originally classified as a Haemophilus species due to its growth requirements and antigentic relatedness to other species in the genus. However, rRNA analysis indicates H. ducreyi is not a true Haemophilus but is more closely related to the Pasteurellaceae family.[2]
- Due to its complex growth requirements H. Ducreyi is difficult to culture.[3]
- The genome of H. ducreyi is a single 1.7-Mb chromosome.
Human Pathogen
- H. ducreyi is an obligate human pathogen.
- H. ducreyi causes chancroid by secreting several virulence factors, the most well-characterized being fimbrialike protein (Flp) and H. ducreyi cytolethal distending toxin (HdCDT). Three Flps, Flp1, Flp2, and Flp3, are suspected to form pili that enable adhesion to fibroblasts and epithelial cells.[4] Active HdCDT is composed of 3 subunits and is homologous to DNase1, causing DNA double stranded breaks, which results in cell cycle arrest and apoptosis human epithelial cells, lymphocytes and fibroblasts.[5]
Strains
- Multi Locus Sequence Analysis of several virulence factors and housekeeping genes has identified class I and class II strains of H. ducreyi causing chancroid, a sexually transmitted genital ulcer disease.[6]
- Such analysis has identified a class I genetically distinct subclade strain of H. ducreyi that may cause non-sexually transmitted cutaneous limb ulcers (CLU).[6]
References
- ↑ Chancroid in Emergency Medicine. Medscape (February 12, 2014). http://emedicine.medscape.com/article/781520-overview#showall Accessed January 12, 2016.
- ↑ Spinola, S. M. (2002). "Immunopathogenesis of Haemophilus ducreyi Infection (Chancroid)". Infection and Immunity. 70 (4): 1667–1676. doi:10.1128/IAI.70.4.1667-1676.2002. ISSN 0019-9567.
- ↑ Lewis, D A (2003). "Chancroid: clinical manifestations, diagnosis, and management". Sexually Transmitted Infections. 79 (1): 68–71. doi:10.1136/sti.79.1.68. ISSN 1368-4973.
- ↑ Spinola, S. M.; Fortney, K. R.; Katz, B. P.; Latimer, J. L.; Mock, J. R.; Vakevainen, M.; Hansen, E. J. (2003). "Haemophilus ducreyi Requires an Intact flp Gene Cluster for Virulence in Humans". Infection and Immunity. 71 (12): 7178–7182. doi:10.1128/IAI.71.12.7178-7182.2003. ISSN 0019-9567.
- ↑ Li, LiQi; Sharipo, Anatoly; Chaves-Olarte, Esteban; Masucci, Maria G.; Levitsky, Victor; Thelestam, Monica; Frisan, Teresa (2002). "The Haemophilus ducreyi cytolethal distending toxin activates sensors of DNA damage and repair complexes in proliferating and non-proliferating cells". Cellular Microbiology. 4 (2): 87–99. doi:10.1046/j.1462-5822.2002.00174.x. ISSN 1462-5814.
- ↑ 6.0 6.1 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. PMC 4361675. PMID 25774793.