A quantitative chemiluminescent ribosomal probe method for monitoring adherence of Haemophilus ducreyi to eukaryotic cells.

This study evaluated a commercially available chemiluminescent-labelled, ribosomal RNA-directed DNA probe (CRP) as a method to quantitate attachment of H. ducreyi to human foreskin fibroblast (HFF) cells. Evaluation of four strains of H. ducreyi demonstrated that the CRP assay was unaffected by eukaryotic cells and its advantages were: (i) quantitation was done after attachment so it did not interfere with the attachment process, and (ii) it was a rapid, reliable method for quantitating bound bacteria, despite bacterial clumping. Gentamicin-killed H. ducreyi attached to both HFF cells and viable controls, suggesting that the adhesins are components constitutively present on the surface of H. ducreyi. This method may be widely applicable, since the probe recognizes most prokaryotic rRNA sequences.