A direct comparison of procedures for the detection of mycoplasma in tissue culture

Mycoplasma contamination of cell cultures has been shown to perturb a number of immunologic parameters. Because such contamination is almost always introduced in the laboratory, the immunologist requires a procedure to screen his cell lines frequently for mycoplasma. Two procedures recently described for the detection of mycoplasma in cell cultures, the uridine-uracil incorporation procedure and a direct fluorescent assay, were compared with the standard procedures of agar culture and transmission electron microscopy. The results with uridine-uracil incorporation were totally non-concordant with those of any of the other 3 procedures and, moreover, were inconsistent through serial assays on the same cell culture. In contrast, the direct fluorescent assay, using the fluorochrome Hoechst 33258, yielded consistent results in full agreement with the agar culture data. Since the fluorescent assay is rapid and has discriminatory capability at least equivalent to that of agar culture, it would appear to be the method of choice for routine screening of cell cultures for mycoplasma.