Table 3.
Comparison of the numbers of positive and negative samples in immunomagnetic separation-multiple displacement amplification (IMS-MDA) real-time PCR, conventional real-time PCR, and culture method in detection of Salmonella spp. in boot swab, drag swab, and litter samples from a chicken farm.
| Real-time PCR1 (24 h enrichment) |
IMS-MDA real-time PCR1 (8 h enrichment) |
||||
|---|---|---|---|---|---|
| Sample type | Culture method | Positive | Negative | Positive | Negative |
| Boot swab (n = 58) | Positive (n = 8) | 7 | 1 | 7 | 1 |
| Negative (n = 50) | 2 | 48 | 3 | 47 | |
| Drag swab (n = 58) | Positive (n = 2) | 2 | 0 | 2 | 0 |
| Negative (n = 56) | 3 | 53 | 3 | 53 | |
| Litter (n = 58) | Positive (n = 9) | 9 | 0 | 9 | 0 |
| Negative (n = 49) | 1 | 48 | 1 | 48 | |
| Total (n = 174) | Positive (n = 19) | 18 | 1 | 18 | 1 |
| Negative (n = 155) | 6 | 149 | 7 | 148 | |
1
P value is 0.51 and Cohen's Kappa index is 0.82 between real-time PCR and culture method, and 0.42 and 0.79 between IMS-MDA real-time PCR and culture method. P value < 0.05 indicates a statistically significant difference with culture method, and Cohen's Kappa index values of between 0.41 and 0.60 indicate clear concordance, those between 0.61 and 0.80 indicated strong concordance, and those between 0.81 and 1.00 indicated nearly complete concordance.