Flow cytometry-based method facilitates optimization of PMA treatment condition for PMA-qPCR method.

Coupling propidium monoazide (PMA) with quantitative PCR (PMA-qPCR) has been successfully applied to specific detection and quantification of viable cells in various samples. The optimal PMA treatment condition is usually determined through qPCR. However, it is a tedious, time consuming and costly process including DNA extraction and qPCR. To overcome this problem, a flow cytometry-based (FCM-based) method was first proposed in this study to replace qPCR for screening of the optimal PMA treatment condition for Helicobacter pylori, since the pure culture treated with PMA was actually a single cell suspension with fluorescent dye. Results showed that the optimal PMA treatment condition (30 μM of PMA and 8 min of exposure time) determined by the novel method was the same as that determined by the qPCR-based method, which demonstrate the feasibility of this approach. In addition, with the comparison of the qPCR-based method, the FCM-based method allows screening of the optimal PMA treatment condition become much more simple, rapid and economical.