Mollicutes, including mycoplasma, acholeplasma, and spiroplasma are parasitic organisms that can be found intracellularly and on the external surfaces of a wide range of eukaryotic host cells. Their size and lack of a rigid cell wall allow them to pass through 0.2 μM filters, and due to a lack of turbidity or cytopathic effects seen during contamination events, they are not easily detected, and almost impossible to remove. Because contamination in cell lines can affect cell growth in culture and influence production yields of biomolecules, it is critical that cell substrates are free of adventitious agents.