Derivation of a Physical Map of the Chromosome of

We have used pulsed-field gel electrophoresis to derive a restriction map of the chromosome of Bordetella pertussis for the enzymes XbaI, Spel, Pacl, and PmeI, which cleave 25, 16, 2, and 1 times, respectively. The apparent size of the genome is 3,750 kb. The positions of genes for major virulence determinants in the vir regulon and of some housekeeping genes were determined. Apart from the previously known linkage of the vir andflha loci, no significant linkage of virulence genes was demonstrated. The genus Bordetella currently contains four species: the human pathogens Bordetella pertussis and Bordetella para-pertussis and the veterinary pathogens Bordetella bronchi-septica and Bordetella avium. In recent years, B. pertussis, the causative agent of the human disease whooping cough, has been the subject of intense genetic analysis. Transposon mutagenesis led to the identification of the genes for several of the major virulence determinants of this organism, i.e., ptx (pertussis toxin), cya (adenylate cyclase-hemolysin), and flza (filamentous hemagglutinin), as well as an importan