Mycoplasma Testing General Program Information Mycoplasma Testing Mycoplasma contamination is a common problem in mammalian cell cultures and can cause spurious assay results. Because mycoplasma species are small and do not make culture media turbid, they cannot be detected by direct visual means. Direct and indirect culture methods are used for detection. The AIDS Reagent Program screens its cell lines and viruses using both of these techniques. Test results are reported on the data sheets that accompany each cell line and virus distributed by the program.
Direct culture is one of the most reliable mycoplasma detection methods.
Agar and broth media are inoculated with the test cell line or virus and then monitored for growth and pH changes for three to four weeks. A negative test result is indicated if there is no color change in the media and no discernable mycoplasma colonies after the appropriate incubation period. A presumptive positive test is indicated by a color change of the medium in the absence of turbidity. Definitive positive is indicated when typical mycoplasma colonies are observed by direct microscopic examination of the agar surface. The purpose of the indicator culture system is to detect cultivar alpha strains of M. hyorhinis that are unable to grow on conventional media.