Haemophilus ducreyi is the causative agent of chancroid, a sexually transmitted genital ulcerative disease. The World Health Organization estimates the annual incidence of chancroid to be over 9 million cases of per year. In addition to the morbidity caused by chancroid, H. ducreyi infection facilitates the heterosexual transmission of the AIDS virus. It has been estimated that there is a 10-300 fold increase in the relative risk of acquiring HIV after a single exposure if the subject has a genital ulcer disease. The mechanisms responsible for pathogenesis, ulcer formation, facilitation of HIV transmission, and the development of protective immunity are poorly understood. Since the landmark publication of Fleishman et al. in 1995, sequencing of prokaryotic genomes has become an accepted strategy for gene discovery, as well as an accepted strategy for enhancing our understanding of basic metabolic processes, and in the case of pathogens, a strategy for increasing our understanding of virulence and antimicrobial resistance mechanisms. In this application, we propose to sequence and annotate the 1.8 Mb chromosome of H. ducreyi. A whole genome shotgun approach will be employed. Additionally, a large fragment library will be prepared in BACs to serve as a scaffolding for the ordering of contigs and for gap closure. The NIH Human Genome Project standard of 1 error per 10,000 assembled bases will be maintained for this project. Primary annotation of the assembled sequence will be performed after assembly. Secondary annotation will be completed in collaboration with Gerald Myers' group at Los Alamos. Dr. Myers' group is developing a integrated data base with detailed annotation of sequences from sexually transmitted pathogens including Treponema pallidum, Neisseria gonorrhoeae and Chlamydia trachomatis. Genome sequences for these organisms are near completion. The availability of the data from this proposed effort as well as data accumulating from other STD and non STD projects will facilitate the development of new testable hypotheses regarding the virulence mechanisms and provide background data necessary for rational vaccine development.
