title: Evaluation of an isogenic hemolysin-deficient mutant in the human model of Haemophilus ducreyi infection.
abstract: 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.
authors.affiliation: Department of Medicine, Indiana University School of Medicine, Indianapolis 46202, USA.
authors.forename: K L
authors.initials: KL
authors.lastname: Palmer
authors.forename: A C
authors.initials: AC
authors.lastname: Thornton
authors.forename: K R
authors.initials: KR
authors.lastname: Fortney
authors.forename: A F
authors.initials: AF
authors.lastname: Hood
authors.forename: R S
authors.initials: RS
authors.lastname: Munson
authors.forename: S M
authors.initials: SM
authors.lastname: Spinola
mesh_terms: D000328:Adult; D002602:Chancroid / Q000382:microbiology* / Q000473:pathology; D004311:Double-Blind Method; D005260:Female; D006191:Haemophilus ducreyi / Q000145:classification / Q000235:genetics / Q000472:pathogenicity*; D006460:Hemolysin Proteins / Q000235:genetics / Q000502:physiology*; D006801:Humans; D008297:Male; D016296:Mutagenesis; D010641:Phenotype; D014774:Virulence
chemical_list: D006460:Hemolysin Proteins