[Accurate titration of mycoplasma culture measured by 50% color change unit assay]

A new method was introduced for precise determination of the live cell titer of mycoplasma culture, and would be a candidate to replace the commonly used CCU (color change unit) assay.

The CCU50 (50% color change unit ) was modified according to the method of TCID50 (50% tissue culture infective dose) assay used for viral titer assessment, and adopted to estimate the live cell titer of mycoplasma. Sensitivity and reproducibility of the CCU50 assay were assessed, and adaptability was checked with M. hyopneumoniae and M. synoviae.

The CCU50 assay showed better reproducibility, sensibility and adaptability than traditional CCU assessment approaches.

The method could be applied to accurate titration determination for mycoplasma, and might be considered as a useful tool for the research of high density fermentation of mycoplasma and development of vaccine.