Evaluation of different hybridization procedures for the detection of mycoplasma contamination in cell cultures.

Cell culture samples were analysed for mycoplasma contaminations with two different DNA probes which have been described earlier. One probe (the H900 probe), derived from the 23S rRNA gene of Mycoplasma hyorhinis, cross-hybridized with virtually all mycoplasmas (including the acholeplasmas). The other probe (the T2 probe), derived from a protein gene of Acholeplasma laidlawii, cross-hybridized with most acholeplasmas. The two probes were compared in three different direct filter hybridization procedures without previous isolation of DNA or RNA. One of the procedures, developed in the present study, gave the highest sensitivity in DNA-RNA hybridization but also worked satisfactorily in DNA-DNA hybridization. The sensitivity of the H900 probe in filter hybridization experiments was compared with the sensitivity of a commercial probe for detection of mycoplasma contaminations in cell cultures. The H900 probe was found to be at least 25 times more sensitive for all cell culture mycoplasmas except for A. laidlawii, for which they were equally sensitive.