Propidium monoazide combined with real-time quantitative PCR underestimates heat-killed Listeria innocua

The combination of propidium monoazide (PMA) and quantitative real-time PCR (qPCR) significantly overestimated the fraction of viable Listeria innocua as compared to plate counts and confocal fluorescence microscopy. Our data imply that PMA-qPCR must be used with caution as an analytical tool for the differentiation between viable and dead bacteria. (C) 2011 Elsevier B.V. All rights reserved.