The sensitivity and specificity of the PCR assay was evaluated in duplicate
using 1 mL of 10-fold serial dilutions (100 ng/mL to 0.1 pg/mL) of purified
genomic DNA from each bacterial species (Section 2.1.1). The assay was repeated
five times under the same conditions. Each cycle threshold (CT) value at which
threshold fluorescence was reached was determined using the software provided
with the Applied Biosystems 7500. Standard curves for each of the target bacteria
were generated by plotting the CT values versus the logarithmic concentration of
the dilution series of target DNA (Fig. 1) and each detection limit (DNA
concentrations) was determined. The specificity of the assay for each target
bacterium was tested using 15 other bacterial species