TABLE 2.
Results of a retrospective evaluation of two pooled NAAT techniques for STEC detection
| Category | Preenrichment poolinga |
Postenrichment pooling |
||||
|---|---|---|---|---|---|---|
| stx1 | stx2 | stx1, stx2 | stx1 | stx2 | stx1, stx2 | |
| No. of positive samples detected/total No. of samples (%) | 8/10 (80) | 9/10 (90) | 8/10 (80) | 10/10 (100) | 10/10 (100) | 10/10 (100) |
| qPCR CT by pooled testingb | ||||||
| Mean (SD) | 32.73 (3.76) | 31.75 (3.36) | 29.48 (5.73), 27.35 (4.32) | 24.17 (2.80) | 25.37 (4.98) | 27.36 (6.61), 26.51 (5.70) |
| Range | 27.52–36.97 | 27.08–36.57 | 20.48–37.05, 20.95–31.8 | 20.05–28.71 | 20.12–33.62 | 21.09–37.12, 18.48–37.08 |
| ΔCT (pooled vs individual qPCR) | ||||||
| Mean (SD) | 12.44 (1.81) | 12.04 (1.87) | 6.24 (1.09), 5.49 (1.40) | 4.18 (0.34) | 5.06 (0.38) | 3.61 (0.34), 3.50 (0.33) |
| Range | 5.14–19.29 | 1.28–19.76 | 2.99–11.37, 1.56–12.12 | 2.22–5.71 | 2.58–6.58 | 2.14–5.40, 1.97–5.62 |
a
Mean (SD) values exclude specimens that were undetected in pools.
b
P < 0.01 compared with prepooled CT by paired Student's t test.