Carbon storage regulator a contributes to the virulence of haemophilus ducreyi in humans by multiple mechanisms

Dharanesh Gangaiah, Wei Li, Kate R. Fortney, Diane M. Janowicz, Sheila Ellinger, Beth Zwickl, Barry P. Katz, Stanley M. Spinola

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


The carbon storage regulator A (CsrA) controls a wide variety of bacterial processes, including metabolism, adherence, stress responses, and virulence. Haemophilus ducreyi, the causative agent of chancroid, harbors a homolog of csrA. Here, we generated an unmarked, in-frame deletion mutant of csrA to assess its contribution to H. ducreyi pathogenesis. In human inoculation experiments, the csrA mutant was partially attenuated for pustule formation compared to its parent. Deletion of csrA resulted in decreased adherence of H. ducreyi to human foreskin fibroblasts (HFF); Flp1 and Flp2, the determinants of H. ducreyi adherence to HFF cells, were downregulated in the csrA mutant. Compared to its parent, the csrA mutant had a significantly reduced ability to tolerate oxidative stress and heat shock. The enhanced sensitivity of the mutant to oxidative stress was more pronounced in bacteria grown to stationary phase compared to that in bacteria grown to mid-log phase. The csrA mutant also had a significant survival defect within human macrophages when the bacteria were grown to stationary phase but not to mid-log phase. Complementation in trans partially or fully restored the mutant phenotypes. These data suggest that CsrA contributes to virulence by multiple mechanisms and that these contributions may be more profound in bacterial cell populations that are not rapidly dividing in the human host.

Original languageEnglish (US)
Pages (from-to)608-617
Number of pages10
JournalInfection and immunity
Issue number2
StatePublished - Feb 2013

ASJC Scopus subject areas

  • Parasitology
  • Microbiology
  • Immunology
  • Infectious Diseases

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