A Haemophilus ducreyi CpxR deletion mutant is virulent in human volunteers

Maria Labandeira-Rey, Dana Dodd, Kate R. Fortney, Beth Zwickl, Barry P. Katz, Diane M. Janowicz, Stanley M. Spinola, Eric J. Hansen

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


Haemophilus ducreyi 35000HP contains a homolog of the CpxRA 2-component signal transduction system, which controls the cell envelope stress response system in other gram-negative bacteria and regulates some important H. ducreyi virulence factors. A H. ducreyi cpxR mutant was compared with its parent for virulence in the human challenge model of experimental chancroid. The pustule formation rate in 5 volunteers was 33% (95% confidence interval [CI], 1.3%-65.3%) at 15 parent sites and 40% (95% CI, 18.1%-61.9%) at 15 mutant sites (P=.35). Thus, the cpxR mutant was not attenuated for virulence. Inactivation of the H. ducreyi cpxR gene did not reduce the ability of this mutant to express certain proven virulence factors, including the DsrA serum resistance protein and the LspA2 protein, which inhibits phagocytosis. These results expand our understanding of the involvement of the CpxRA system in regulating virulence expression in H. ducreyi.

Original languageEnglish (US)
Pages (from-to)1859-1865
Number of pages7
JournalJournal of Infectious Diseases
Issue number12
StatePublished - Jun 15 2011

ASJC Scopus subject areas

  • Immunology and Allergy
  • Infectious Diseases


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