Mycoplasma Infection Mediates Sensitivity of Multidrug-Resistant Cell Lines to Tiopronin: A Cautionary Tale.

We previously reported that some, but not all, multidrug-resistant cells that overexpressed various drug-resistance transporters were collaterally sensitive to tiopronin. In recent follow-up studies, we discovered that sensitivity to tiopronin in the original study was mediated by infection of the cells by a human-specific strain of mycoplasma. These results strongly support the need to constantly monitor cells for mycoplasma infection and keep stored samples of all cells that are used for in vitro studies.