Table 4.
Occurrence of target virulence factors and “big 6” non-O157 serogroups in the initial PCR screen of the enriched samples from each farm (A–F).
| Farm | Number of samples tested | Percent positive for virulence gene combinationsa | Percent positive for serogroupsa | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| stx 1, stx 2 , eaeA, ehxA | stx 1, stx 2 , ehxA | stx 1 or stx 2 , eaeA, ehxA | stx 1 , ehxA | stx 2 , ehxA | eaeA, ehxA | eaeA | stx 1 or stx 2 alone | O111 | O26 | O121 | O145 | O45 | O103 | ||
| A | 25 | 6.6 | 2.9 | 0 | 0 | 1.5 | 0 | 0 | 0 | 0 | 0 | 5.9 | 0 | 3.7 | 5.1 |
| B | 44 | 13.2 | 2.9 | 0 | 0 | 0 | 0 | 0 | 0 | 0.7 | 9.6 | 13.2 | 0 | 2.2 | 16.2 |
| C | 9 | 2.9 | 0 | 0 | 0 | 0.7 | 2.2 | 0.7 | 0 | 0 | 2.9 | 0.7 | 1.5 | 3.7 | 5.1 |
| D | 24 | 1.5 | 4.4 | 1.5 | 0 | 0 | 0.7 | 0 | 2.9 | 0 | 8.1 | 0 | 0.7 | 0.7 | 10.3 |
| E | 18 | 5.9 | 2.9 | 0.7 | 0 | 0 | 0 | 0 | 0 | 3.7 | 4.4 | 0.7 | 0.7 | 8.1 | 7.4 |
| F | 16 | 0 | 2.2 | 0 | 1.5 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
|
| |||||||||||||||
| Total | 136 | 30.1 | 15.4 | 2.2 | 1.5 | 2.2 | 2.9 | 0.7 | 2.9 | 4.4 | 25 | 20.6 | 2.9 | 18.4 | 44.1 |
aThe percentage of samples positive were calculated by dividing the number of positive samples for each category in the initial PCR screen by the total number of samples (n = 136) collected.