Detection of cell culture mycoplasmas by a genetic probe

The utility of a genetic probe prepared against mycoplasmal ribosomal RNA was evaluated. The probe consisted of a tritiated DNA probe prepared with reverse transcriptase against Mycoplasma and Acholeplasma. Using a batch process without Southern blots and autoradiography, the probe assay detected mycoplasma infection in 27 of 52 cell cultures, an incidence of 51.9%. No false-positives were detected. Two false-negatives occurred; these were unusual mycoplasma infections of cell cultures grown in serum-free media. The sensitivity of the probe varied with mycoplasma species, from 9.3 X 10(3) for M. arginini to 2.6 X 10(6) for M. orale. The assay is rapid, taking only 2-3 h.