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. 2006 Jun;72(6):3879–3886. doi: 10.1128/AEM.02266-05

TABLE 3.

CT values obtained from TaqMan PCR on DNA extracted directly and after enrichment from substrates that were amended with a dilution series of S. enterica serovar Enteritidis

Method No. of CFUa CT value per amount of serovar Enteritidis inb:
Soil
Manure
Compost
S4Oc S4C S5O S5C S7O S7C S9O S9C M1 M2 M3 M4 M5 M6 CA CB
Direct Z × 107 25.18 27.09 25.79 24.24 24.41 23.70 26.48 25.52 21.01 Nc 20.20 20.05 23.04 21.13 N 24.39
Z × 106 28.40 30.15 27.53 27.08 26.08 26.68 26.42 24.70 23.78 N 24.36 24.16 33.76 25.26 26.48 25.72
Z × 105 32.88 34.50 30.30 31.56 30.61 28.85 28.63 29.51 27.57 N 27.27 27.40 N 28.43 32.69 29.54
Z × 104 34.24 35.11 33.10 33.33 33.63 31.87 33.31 35.20 31.50 N 30.90 31.65 N 34.69 33.98 32.77
Z × 103 37.15 39.12 36.17 N 38.24 34.44 36.17 34.92 36.40 N 36.52 34.83 N N N 37.37
Z × 102 N N N N N N N N N N N N N N N N
Neg N N N N N N N N N N N N N N N N
Enrichment Z × 102 17.38 15.73 15.74 16.16 17.47 15.75 16.06 15.86 16.93 15.62 16.80 16.96 16.09 16.15 20.71 24.63
Z × 101 18.69 16.76 16.80 16.28 19.68 18.09 17.64 16.59 19.46 16.26 17.28 19.32 16.23 16.11 22.27 24.20
Z × 100 20.90 18.63 17.58 17.17 21.51 34.51 19.39 18.38 22.16 15.98 34.81 21.19 16.20 16.99 23.88 33.31
Z × 10−1 N N N N N N N 19.84 22.42 N N N N N N N
Neg N N N N N N N N N N N N N N N N
a

Calculated number of CFU of S. enterica serovar Enteritidis added to 100 mg of each substrate prior to DNA extraction. Z was different for each time-related group: Z = 1.2 for group 1 (S4O and S4C); Z = 1.3 for group 2 (S5O and S5C); Z = 1.4 for group 3 (S7O and S7C); Z = 1.6 for group 4 (S9O and S9C); Z = 1.7 for group 5 (M1 and M2); Z = 0.8 for group 6 (M3 and M4); Z = 1.8 for group 7 (M5 and M6); and Z = 1.2 for group 8 (CA and CB). Each group was treated in 1 day and in a similar manner using fresh bacterial cultures each time. Neg, negative control.

b

The amount was calculated from plating. A sample negative for serovar Enteritidis is indicated by N.

c

N represents the substrate tested for DNA extraction and subsequent TaqMan PCR.