Experimental infection of human volunteers with Haemophilus ducreyi: fifteen years of clinical data and experience

J Infect Dis. 2009 Jun 1;199(11):1671-9. doi: 10.1086/598966.

Abstract

Haemophilus ducreyi causes chancroid, which facilitates transmission of human immunodeficiency virus type 1. To better understand the biology of H. ducreyi, we developed a human inoculation model. In the present article, we describe clinical outcomes for 267 volunteers who were infected with H. ducreyi. There was a relationship between papule formation and estimated delivered dose. The outcome (either pustule formation or resolution) of infected sites for a given subject was not independent; the most important determinants of pustule formation were sex and host effects. When 41 subjects were infected a second time, their outcomes segregated toward their initial outcome, confirming the host effect. Subjects with pustules developed local symptoms that required withdrawal from the study after a mean of 8.6 days. There were 191 volunteers who had tissue biopsy performed, 173 of whom were available for follow-up analysis; 28 (16.2%) of these developed hypertrophic scars, but the model was otherwise safe. Mutant-parent trials confirmed key features in H. ducreyi pathogenesis, and the model has provided an opportunity to study differential human susceptibility to a bacterial infection.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Chancroid / genetics
  • Chancroid / microbiology*
  • Chancroid / pathology
  • Chancroid / transmission
  • Female
  • Haemophilus ducreyi / pathogenicity*
  • Humans
  • Male
  • Middle Aged
  • Recurrence
  • Skin Diseases, Vesiculobullous / pathology
  • Young Adult