Detection of tetracycline-resistant strains of Ureaplasma urealyticum by hybridization assays.

Five wild-type strains of tetracycline-resistant Ureaplasma Ureaplasma urealyticum and one tetracycline-sensitive Ureaplasma urealyticum strain were tested for presence of the tetM sequence by hybridization assays. Two sorts of probes were used, a plasmid containing the tetM fragment and the tetM fragment alone. Two sorts of label were used for each, digoxigenin and radio-labelling. Both purified DNA at various concentrations and non-purified DNA in the pellet from a 10 ml culture were used as targets. The digoxigenin-labelled whole plasmid probe was as specific as the insert alone when hybridized with non-purified DNA, and was more sensitive than radio-labelled probes.