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Table 8 Comparisons of identification of D. nodosus by the aprB2 rtPCR and culture/gelatinase gel test from subsets of presence/absence or both of foot lesions from the clinically affected flocks, consisting of 135 clinically affected sheep and 35 clinically healthy sheep

From: Assessment of a rtPCR for the detection of virulent and benign Dichelobacter nodosus, the causative agent of ovine footrot, in Australia

Flocks Sheep clinical status (foot lesions) No. sheep tested aprB2 PCR Run and/or Cut-off Culture Gelatinase Thermolabile (Benign) vs aprB2 PCR Percentage positive results
Concordant results Culture +ve PCR + ve p value Kappa Culture aprB2 PCR
+ve -ve PCR -ve Culture -ve
12 to 24 +ve 135 Run 1 / 40 7 108 2 18 0.0008 0.348 6.7% 18.5%
12 to 24 +ve 135 Run 1 / 35 7 110 2 16 0.0022 0.378 6.7% 17.0%
12 to 14 -ve 35 Run 1 / 40 0 33 0 2 0.4795 0 0.0% 5.7%
12 to 14 -ve 35 Run 2 / 40 0 34 0 1 1 0 0.0% 2.9%
12 to 14 -ve 35 Run 1 / 35 0 34 0 1 1 0 0.0% 2.9%
12 to 14 -ve 35 Run 2 / 35 0 34 0 1 1 0 0.0% 2.9%
12 to 14 -ve & + ve 72 Run 1 / 40 1 60 1 10 0.0159 0.112 2.8% 15.3%
12 to 14 -ve & + ve 72 Run 2 / 40 1 62 1 8 0.0455 0.143 2.8% 12.5%
12 to 14 -ve & + ve 72 Run 1 / 35 1 63 1 7 0.0771 0.163 2.8% 11.1%
12 to 14 -ve & + ve 72 Run 2 / 35 1 63 1 7 0.0771 0.163 2.8% 11.1%
12 to 24 -ve & + ve 170 Run 1 / 40 7 141 2 20 0.0003 0.336 5.3% 15.9%
12 to 24 -ve & + ve 170 Run 1 / 35 7 141 2 17 0.0013 0.376 5.3% 14.1%
  1. The p-value for McNemar’s test for independence between culture gelatinase thermostable (benign) and aprB2 PCR result is shown. Detection rates of both culture and rtPCR are presented as percentage positive results