Evaluation of an isogenic hemolysin-deficient mutant in the human model of Haemophilus ducreyi infection.
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.
Palmer
K L
KL
Department of Medicine, Indiana University School of Medicine, Indianapolis 46202, USA.
Thornton
A C
AC
Fortney
K R
KR
Hood
A F
AF
Munson
R S
RS
Spinola
S M
SM
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
D006460:Hemolysin Proteins