Inactivation of the Haemophilus ducreyi luxS Gene Affects the Virulence of This Pathogen in Human Subjects

Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, USA.
The Journal of Infectious Diseases (Impact Factor: 5.78). 07/2009; 200(3):409-16. DOI: 10.1086/600142
Source: PubMed

ABSTRACT Haemophilus ducreyi 35000HP contains a homologue of the luxS gene, which encodes an enzyme that synthesizes autoinducer 2 (AI-2) in other gram-negative bacteria. H. ducreyi 35000HP produced AI-2 that functioned in a Vibrio harveyi-based reporter system. A H. ducreyi luxS mutant was constructed by insertional inactivation of the luxS gene and lost the ability to produce AI-2. Provision of the H. ducreyi luxS gene in trans partially restored AI-2 production by the mutant. The luxS mutant was compared with its parent for virulence in the human challenge model of experimental chancroid. The pustule-formation rate in 5 volunteers was 93.3% (95% confidence interval, 81.7%-99.9%) at 15 parent sites and 60.0% (95% confidence interval, 48.3%-71.7%) at 15 mutant sites (1-tailed P < .001). Thus, the luxS mutant was partially attenuated for virulence. This is the first report of AI-2 production contributing to the pathogenesis of a genital ulcer disease.


Available from: Maria Labandeira-Rey, Jun 04, 2015
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