Association of Haemophilus ducreyi with cell-culture lines.

The association of Haemophilus ducreyi with epithelial cell cultures was studied by light microscopy, electronmicroscopy and viable counts. Associated organisms were engulfed by epithelial cells and sequestered from the cell-surface environment. Large numbers of organisms within epithelial cells appeared to induce cell lysis and release of H. ducreyi. Such a mechanism occurring in vivo may assist H. ducreyi to evade the bactericidal action of polymorphonuclear leucocytes and may explain some of the tissue damage seen in genital ulcers caused by H. ducreyi.