Rapid and Accurate Detection of Bacteriophage Activity against Escherichia coli O157:H7 by Propidium Monoazide Real-Time PCR

Figure 2

Effect of propidium monoazide (PMA) concentration on detection of live or compromised/damaged E. coli O157:H7 R508N cells by qPCR. Live or heat-killed cells were incubated with increasing concentrations of PMA. 300 μM PMA was not included in incubations with dead cells. Amplification of DNA was not detected for 100 and 200 μM PMA for 3 and 5 log₁₀CFU/mL compromised/damaged cells. Each bar presents the mean ± standard deviation for two independent replicates. (threshold cycle) > 35, no signal or only a weak signal was detected.