Some samples may have been exposed to bacteria or have been treated with antibacterial substances during production, which can affect the growth of mycoplasmas. In particular, antibiotics and enzymes produced by bacteria can directly kill or inhibit mycoplasmas, resulting in false negative results in testing. Therefore, although regulations do not mandate this, many Japanese pharmaceutical companies, driven by their high quality standards, have added a filter-based culture process to their mycoplasma testing to better prevent mycoplasma contamination.
If bacteria are present in the solution, mycoplasma will definitely not be viable. Even if bacteria were present earlier and were later removed, they would have already severely inhibited or completely prevented mycoplasma growth. The main reasons are: