A New Method to Estimate Mycoplasma gallisepticum Bacterial Concentration in Culture

The ability to rapidly estimate bacterial numbers in a pure culture is an important research tool, often performed by measuring the optical density of the culture. However, this method is of limited use with mycoplasma cultures. Therefore, a new method for estimating Mycoplasma gallisepticum cell numbers in a pure culture was developed based on the fluorescent measurement of genomic DNA from lysed cells. Actual Mycoplasma gallisepticum counts obtained from either Color Change Units (CCU) or Colony Forming Units (CFU) were used to create equations to estimate mycoplasma concentration from either DNA concentration data obtained from lysed cells or optical density data from mycoplasma in media. The results suggest that calculated counts are slightly more accurate than those obtained from OD600 data. The results further show that calculating culture concentration using the DNA concentration has a wider range compared to using OD600 data. Results also showed that equations generated using one M. gallisepticum strain could work for a second M. gallisepticum strain. However, it was also shown that the equations were not accurate for a different mycoplasma strain. These results suggest tha