Physical genome map of Haemophilus ducreyi KC1 (CIP 542[superscript]t)

by Talbot, Hazel

Haemophilus ducreyi is the causative agent of chancroid, an ulcerative sexually transmitted disease. Little basic information regarding the genetics of H. ducreyi is available. Therefore, a physical restriction map of the genome of the type strain of the species, CIP 542, was constructed on which newly discovered genes can be placed and which can be used for epiderniological and taxonornic purposes. KCI, a commonly used strain of CIP 542 was chosen for physical mapping. Mapping utilized pulsed-field gel electrophoresis techniques and the following strategies: (1) the use of four restriction endonucleases Ascl, Notl, Sfil and 1-Ceul which cut the genorne at 12, 9, 4 and 6 sites, respectively (Il) double digests (III) sequential reciprocal digests (IV) cross-hybridization. The chromosome was found to be circular 1771 k 43 kb with six copies of 16s and 23s rRNA. Twenty-six other genes were positioned on the map, including those associated with virulence; hhdS,A (hemolysin gene), hupA (hemogiobin-binding outer membrane protein gene), momp (OMP A homologue gene) and ftpA (finetangled-pilus gene). The pulsed-field electrophoretic profile of KCI was also found to be significantly different frorn the ATCC strain of CIP 542. Thus, at least 2 different strains have been designated CIP 542. This may help resolve some controversies in the literature regarding virulence of this strain.