Abstract
A combination of propidium monoazide (PMA) with quantitative PCR (PMA-qPCR) have been successfully applied to distinguish between viable and dead microorganisms. However, PMA treatment of the filtered bacteria was reported to show no effect of discrimination. In this study, the efficient filtration procedure was examined to enumerate viable Escherichia coli by PMA-qPCR. After filtration, a final concentration of PMA treatment was regulated with ultrapure water and PBS solution. The treatment with 50μM PMA indicated no significant difference in viable cells between ultrapure water and PBS solution. The treatment with 100μM showed PBS solution had viable cells as high as suspended ones, although ultrapure water resulted in lower viable cells than suspended cells. In addition, the PMA treatment of the membrane filter fixed in the holder was more efficient than those of the filters unfixed.
