Evaluation of an isogenic hemolysin-deficient mutant in the human model of Haemophilus ducreyi infection

K. L. Palmer, A. C. Thornton, K. R. Fortney, A. F. Hood, R. S. Munson, S. M. Spinola

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39 Scopus citations


Haemophilus ducreyi causes the genital ulcerative disease chancroid. One putative virulence factor of H. ducreyi is a pore-forming hemolysin that displays toxicity against human fibroblasts and keratinocytes. In order to test the role of the hemolysin in pathogenesis, an isogenic hemolysin- deficient mutant was constructed, designated 35000HP-RSM1. The lipooligosaccharide, outer membrane protein patterns, and growth attributes of 35000HP-RSM1 were identical to its parent, 35000HP. Human subjects were challenged on the upper arm with the isogenic isolates in a double-blinded, randomized, escalating dose-response study. Pustules developed at a similar rate at sites inoculated with the mutant or parent. The cellular infiltrate and bacterial load in lesions were also similar. These results indicate the hemolysin does not play a role in pustule formation. Due to the limitations of this model, the role of the hemolysin at later stages of infection could not be determined.

Original languageEnglish
Pages (from-to)191-199
Number of pages9
JournalJournal of Infectious Diseases
Issue number1
StatePublished - 1998

Bibliographical note

Funding Information:
Received 22 September 1997; revised 11 February 1998. Presented in part: International Congress of Sexually Transmitted Diseases, Seville, Spain, October 1997. Informed consent was obtained from the subjects for participation and for HIV serology, in accordance with the human experimentation guidelines of the US Department of Health and Human Services and the Institutional Review Board of Indiana University-Purdue University at Indianapolis. Grant support: NIH (AI-34967, AI-27863, AI-30006, RR-00750, and T32DK-07532). Reprints or correspondence: Dr. Stanley M. Spinola, Indiana University School of Medicine, Dept. of Medicine, Emerson Hall, Room 435, 545 Barnhill Dr., Indianapolis, IN 46202 (sspinola@iupui.edu).

ASJC Scopus subject areas

  • Immunology and Allergy
  • Infectious Diseases


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