Why is mycoplasma testing important and how is it performed?

Mycoplasma contamination is a major concern for mammalian cell cultures because these bacteria lack cell walls (not affected by common antibiotics), are difficult to detect visually, and can alter cell physiology, gene expression, and experimental results. Testing methods include: culture-based (inoculating indicator cell lines and detecting growth - sensitive but slow, 28 days), PCR/qPCR (detecting mycoplasma DNA - rapid, sensitive, commonly used), and indicator cell culture with DNA staining (Hoechst, DAPI - detects characteristic fluorescent foci). Regulatory requirements mandate testing of cell banks and biological products. Prevention includes: using certified mycoplasma-free reagents, routine testing, quarantine of new cell lines, and avoiding mouth pipetting. Contaminated cultures should be discarded or treated with validated eradication protocols.